View Filing Data

Depreciation, depletion and amortization

(27,285)

41,408

33,278

121,398

97,434

Taxes - property, production and severance

10,213

9,161

31,201

24,598

Impairment of long-lived assets

26,868

Other operating expenses

216

259

1,679

562

Total operating expenses

168,998

209,951

686,573

776,908

Operating income

77,810

39,572

168,449

134,099

Interest charges -

Interest expense incurred (including amortization of debt issuance costs, premiums, discounts and realized settlements on interest rate swaps)

(27,475)

(29,303)

(85,151)

(87,099)

Allowance for funds used during construction - borrowed

1,127

3,520

2,608

9,874

Capitalized interest

175

2,981

467

8,198

Unrealized gain (loss) on interest rate swaps, net

605

(38,246)

(2,902)

(40,608)

Interest income

364

536

1,428

1,547

Allowance for funds used during construction - equity

196

189

668

676

Other income, net

(287)

528

2,073

1,763

Total other income (expense)

(25,295)

(59,795)

(80,809)

(105,649)

Income (loss) before equity in earnings (loss) of unconsolidated subsidiaries and income taxes

52,515

(20,223)

87,640

28,450

Equity in earnings (loss) of unconsolidated subsidiaries

(12)

1,076

Income tax benefit (expense)

(17,914)

9,017

(30,057)

(7,915)

Income (loss) from continuing operations

34,623

(11,163)

57,571

21,611

Income (Loss) from Discontinued Operations, Net of Tax

(166)

^[1]

638

(6,810)

^[1]

2,526

Net income (loss) available for common stock

$ 34,457

$ (10,525)

$ 50,761

$ 24,137

Income (loss) per share, Basic-

Income (loss) from continuing operation, per share

$ 0.79

$ (0.29)

$ 1.31

$ 0.55

Income (loss) from discontinued operations, per share

0.00

0.02

(0.16)

0.07

Total income (loss) per share, Basic

0.79

(0.27)

1.15

0.62

Income (loss) per share, Diluted -

Income (loss) from continuing operations, per share

0.78

(0.29)

1.31

0.54

Income (loss) from discontinued operations, per share

0.00

0.02

(0.16)

0.07

Total income (loss) per share, Diluted

$ 0.78

$ (0.27)

$ 1.15

$ 0.61

Weighted average common shares outstanding:

Basic

43,847

39,145

43,792

39,105

Diluted

44,108

39,145

44,026

39,792

Dividends paid per share of common stock

$ 0.370

$ 0.365

$ 1.110

$ 1.095

[1]	Includes transaction related costs, net of tax, of $0.2 million and $2.5 million for three and nine months ended Sept. 30, 2012, respectively.

Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Statement of Comprehensive Income - USD ($) $ in Thousands	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net Income (Loss) Attributable to Parent	$ 34,457	$ (10,525)	$ 50,761	$ 24,137
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(3,591)	1,922	(3,004)	(991)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	28	285	(1,333)	1,907
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(3,563)	2,207	(4,337)	916
Other Comprehensive Income (Loss), net of tax	$ 30,894	$ (8,318)	$ 46,424	$ 25,053

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=20435746&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A7
-Appendix A

Reference 12: http://www.xbrl.org/2003/role/presentationRef
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-Name Emerging Issues Task Force (EITF)
-Number 87-21
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 14: http://www.xbrl.org/2003/role/presentationRef
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

Net of tax amount of the income statement impact of the reclassification adjustment of accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges realized in net income. Also includes reclassification adjustments of an entity's share of an equity investee's deferred hedging gain (loss) realized in net income.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=20435746&loc=d3e689-108580

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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 24
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 18, 19
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Net of tax amount, before reclassification adjustments, of the change in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Also includes an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Statement of Comprehensive Income (Parantheticals) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ 1,204	$ (1,215)	$ 1,092	$ 653
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax	$ 13	$ (129)	$ 890	$ (985)

Tax effect of the income statement impact of the reclassification adjustment of accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges realized in net income. Also includes reclassification adjustments of an entity's share of an equity investee's deferred hedging gain (loss) realized in net income.

Net income (loss) available for common stock

Condensed Consolidated Balance Sheets (Parentheticals) - $ / shares	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Common Stock Par Value	$ 1	$ 1	$ 1
Common Stock, Shares Authorized	100,000,000	100,000,000	100,000,000
Common Stock, Shares, Issued	44,250,588	43,957,502	39,491,616
Common Stock, Shares, Outstanding	44,175,168	43,924,736	39,463,575
Treasury Stock, Shares	75,420	32,766	28,041

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Current assets:
Cash and cash equivalents	$ 247,192	$ 21,628	$ 30,198
Restricted cash and equivalents	7,302	9,254	4,080
Accounts receivable, net	104,482	156,774	102,673
Materials, supplies and fuel	80,900	84,064	84,607
Derivative assets, current	16,063	18,583	12,177
Income tax receivable, net	11,869	9,344	4,728
Deferred income tax assets, net, current	33,681	37,202	37,931
Regulatory assets, current	24,606	59,955	45,713
Other current assets	44,823	21,266	25,269
Assets of discontinued operations	0	340,851	332,503
Total current assets	570,918	758,921	679,879
Investments	16,273	17,261	17,338
Property, plant and equipment	3,950,222	3,724,016	3,656,762
Less accumulated depreciation and depletion	(1,253,808)	(934,441)	(931,299)
Total property, plant and equipment, net	2,696,414	2,789,575	2,725,463
Other assets:
Goodwill	353,396	353,396	353,396
Intangible assets, net	3,675	3,843	3,899
Derivative assets, non-current	1,167	1,971	3,246
Regulatory assets, non-current	191,935	182,175	142,267
Other assets, non-current	19,850	19,941	20,081
Total other assets	570,023	561,326	522,889
TOTAL ASSETS	3,853,628	4,127,083	3,945,569
Current liabilities:
Accounts payable	69,138	104,748	91,628
Accrued liabilities	179,284	151,319	161,650
Derivative liabilities, current	86,509	84,367	101,312
Regulatory liabilities, current	10,705	16,231	10,568
Notes Payable	225,000	345,000	359,000
Current maturities of long-term debt	328,310	2,473	2,893
Liabilities of discontinued operations	0	173,929	171,685
Total current liabilities	898,946	878,067	898,736
Long-term debt, net of current maturities	942,950	1,280,409	1,282,194
Deferred credits and other liabilities:
Deferred income tax liabilities, net, non-current	338,194	300,988	317,864
Derivative liabilities, non-current	41,410	49,033	22,475
Regulatory liabilities, non-current	120,491	108,217	85,074
Benefit plan liabilities	167,690	177,480	124,214
Other deferred credits and other liabilities	129,630	123,553	127,007
Total deferred credits and other liabilities	797,415	759,271	676,634
Commitments and contingencies (See Notes 6, 7, 9, 11, 12 and 14)
Common stock —
Common stock $1 par value; 100,000,000 shares authorized; issued 44,250,588; 43,957,502 and 39,491,616 shares, respectively	44,251	43,958	39,492
Additional paid-in capital	731,176	722,623	604,945
Retained earnings	478,459	476,603	467,043
Treasury stock at cost – 75,420; 32,766 and 28,041 share, respectively	(2,354)	(970)	(810)
Accumulated other comprehensive income (loss)	(37,215)	(32,878)	(22,665)
Total stockholders' equity	1,214,317	1,209,336	1,088,005
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 3,853,628	$ 4,127,083	$ 3,945,569

Condensed Consolidated Statements of Cash Flows - USD ($)
$ in Thousands

9 Months Ended

Sep. 30, 2012

Sep. 30, 2011

Operating activities:

$ 50,761

$ 24,137

(Income) loss from discontinued operations, net of tax

6,810

(2,526)

Income (loss) from continuing operations

57,571

21,611

Adjustments to reconcile net income (loss) to net cash provided by operating activities:

Depreciation, depletion and amortization

121,398

97,434

Deferred financing cost amortization

5,301

5,040

Impairment of long-lived assets

26,868

Derivative fair value adjustments

(3,522)

(2,305)

Unrealized mark-to-market (gain) loss on interest rate swaps

(27,285)

Stock compensation

5,974

4,840

2,902

40,608

Deferred income taxes

28,718

20,854

Allowance for funds used during construction - equity

(668)

(676)

Employee benefit plans

15,737

10,930

Other adjustments, net

3,505

3,177

Changes in certain operating assets and liabilities:

Materials, supplies and fuel

3,085

(21,692)

Accounts receivable, unbilled revenues and other current assets

43,447

50,649

Accounts payable and other current liabilities

(22,042)

(51,846)

Regulatory assets

15,544

22,357

Regulatory liabilities

(1,983)

5,041

Contributions to defined benefit pension plans

(25,000)

(11,050)

Other operating activities, net

(1,067)

(1,755)

Net cash provided by operating activities of continuing operations

248,483

193,217

Net cash provided by (used in) operating activities of discontinued operations

21,184

13,309

Net cash provided by operating activities

269,667

206,526

Investing activities:

Property, plant and equipment additions

(261,414)

(326,543)

Proceeds from sale of assets

268,482

583

Investment in notes receivable

(21,832)

Other investing activities

5,057

1,051

Net cash provided by (used in) investing activities of continuing operations

(9,707)

(324,909)

Proceeds from sale of business operations

108,837

Net cash provided by (used in) investing activities of discontinued operations

(824)

(1,953)

Net cash provided by (used in) investing activities

98,306

(326,862)

Financing activities:

Dividends paid on common stock

(48,904)

(43,169)

Common stock issued

3,835

2,199

Short-term borrowings - issuances

62,453

770,000

Short-term borrowings - repayments

(182,453)

(560,000)

Long-term debt - repayments

(11,647)

(6,169)

Other financing activities

(2,833)

(28)

Net cash provided by (used in) financing activities of continuing operations

(179,549)

162,833

Net cash provided by (used in) financing activities of discontinued operations

(157)

Net cash provided by (used in) financing activities

(179,549)

162,676

Net change in cash and cash equivalents

188,424

42,340

Cash and cash equivalents:

Cash and cash equivalents, beginning of period

^[1]

58,768

32,438

Cash and cash equivalents, end of period

$ 247,192

$ 74,778

^[1]

[1]	Includes cash of discontinued operations of $37.1 million, $44.6 million and $16.0 million at Dec. 31, 2011, Sept. 30, 2011 and Dec. 31, 2010, respectively.

Condensed Consolidated Statements of Cash Flows Parantheticals - USD ($) $ in Millions	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	$ 37.1	$ 44.6	$ 16.0

For the disposal group, including a component of the entity (discontinued operation), cash includes currency on hand as well as demand deposits with banks or financial institutions. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

Supplemental Cash Flow Information [Abstract]

Management's Statement	9 Months Ended
Management's Statement	Sep. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Management's Statement	MANAGEMENT'S STATEMENT The unaudited Condensed Consolidated Financial Statements included herein have been prepared by Black Hills Corporation (together with our subsidiaries the "Company," "us," "we," or "our"), pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to such rules and regulations; however, we believe that the footnotes adequately disclose the information presented. These Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our 2011 Annual Report on Form 10-K filed with the SEC. Accounting methods historically employed require certain estimates as of interim dates. The information furnished in the accompanying Condensed Consolidated Financial Statements reflects all adjustments, including accruals, which are, in the opinion of management, necessary for a fair presentation of the Sept. 30, 2012, December 31, 2011 and Sept. 30, 2011 financial information and are of a normal recurring nature. Certain industries in which we operate are highly seasonal, and revenue from, and certain expenses for, such operations may fluctuate significantly among quarterly periods. Demand for electricity and natural gas is sensitive to seasonal cooling, heating and industrial load requirements, as well as changes in market price. In particular, the normal peak usage season for gas utilities is November through March and significant earnings variances can be expected between the Gas Utilities segment's peak and off-peak seasons. Due to this seasonal nature, our results of operations for the three and nine months ended Sept. 30, 2012 and Sept. 30, 2011, and our financial condition as of Sept. 30, 2012, December 31, 2011, and Sept. 30, 2011 are not necessarily indicative of the results of operations and financial condition to be expected as of or for any other period. All earnings per share amounts discussed refer to diluted earnings per share unless otherwise noted. On Feb. 29, 2012, we sold our Energy Marketing segment, which resulted in this segment being classified as discontinued operations. For comparative purposes, all prior periods presented have been restated to reflect the classification of this segment as discontinued operations. For further information see Note 17. Certain prior year data presented in the financial statements has been reclassified to conform to the current year presentation. Specifically, the Company has reclassified deferred financing cost amortization into a separate line on the Condensed Consolidated Statements of Cash Flows. This reclassification had no effect on total assets, net income, cash flows or earnings per share.

Recently Adopted and Recently Issued Accounting Standards and Legislation	9 Months Ended
	Sep. 30, 2012
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Adopted and Recently Issued Accounting Standards and Legislation	RECENTLY ADOPTED AND RECENTLY ISSUED ACCOUNTING STANDARDS AND LEGISLATION Recently Adopted Accounting Standards and Legislation Other Comprehensive Income: Presentation of Comprehensive Income, ASU 2011-05 and ASU 2011-12 FASB issued an accounting standards update amending accounting guidance for Comprehensive Income to improve the comparability, consistency and transparency of reporting of comprehensive income. The update amends existing guidance by allowing only two options for presenting the components of net income and other comprehensive income: (1) in a single continuous financial statement, statement of comprehensive income or (2) in two separate but consecutive financial statements, consisting of an income statement followed by a separate statement of other comprehensive income. Also, items that are reclassified from other comprehensive income to net income must be presented on the face of the financial statements. ASU 2011-05 requires retrospective application, and is effective for the fiscal years, and interim periods within those years beginning after Dec. 15, 2011. In December 2011, FASB issued ASU 2011-12, which indefinitely deferred the provisions of ASU 2011-05 requiring the presentation of reclassification adjustments on the face of the financial statements for items reclassified from other comprehensive income to net income. At Dec. 31, 2011, we elected to early adopt the provisions of ASU 2011-05 as amended by ASU 2011-12. The adoption changed our presentation of certain financial statements, but did not have any other impact on our financial statements. Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements, ASU 2011-04 In May 2011, FASB issued an accounting standards update amending accounting guidance for Fair Value Measurements and Disclosures to achieve common fair value measurement and disclosure requirements between GAAP and IFRS. Additional disclosure requirements in the update include: (1) for Level 3 fair value measurements - quantitative information about unobservable inputs used, a description of the valuation processes used by the entity, and a qualitative discussion about the sensitivity of the measurements to changes in the unobservable inputs; (2) for an entity's use of a non-financial asset that is different from the asset's highest and best use - the reason for the difference; (3) for financial instruments not measured at fair value but for which disclosure of fair value is required - the fair value hierarchy level in which the fair value measurements were determined; and (4) the disclosure of all transfers between Level 1 and Level 2 of the fair value hierarchy. ASU 2011-04 is effective for fiscal years, and interim periods within those years, beginning after Dec. 31, 2011. The amendment required additional details in notes to financial statements, but did not have any other impact on our financial statements. Additional disclosures are included in Notes 12 and 13. Intangibles - Goodwill and Other: Testing Goodwill for Impairment, ASU 2011-08 In September 2011, the FASB issued an amendment to accounting guidance to Intangibles - Goodwill and Other to provide an option to perform a qualitative assessment to determine whether further impairment testing of goodwill is necessary. Specifically, an entity has the option to first assess qualitative factors to determine whether it is necessary to perform the current two-step test. If an entity believes, as a result of its qualitative assessment, that it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, the quantitative impairment test is required. Otherwise, no further testing is required. This standard is effective for annual and interim goodwill impairment testing performed for fiscal years beginning after Dec. 15, 2011. We perform our annual impairment testing in November of each year. The adoption of this standard will not have an impact on our financial statements. Recently Issued Accounting Standards and Legislation Balance Sheet: Disclosure about Offsetting Assets and Liabilities, ASU 2011-11 In December 2011, the FASB issued revised accounting guidance to amend accounting guidance for Balance Sheet related to the existing disclosure requirements for offsetting financial assets and liabilities to enhance current disclosures, as well as to improve comparability of balance sheets prepared under GAAP and IFRS. The revised disclosure guidance affects all companies that have financial instruments and derivative instruments that are either offset in the balance sheet (i.e., presented on a net basis) or subject to an enforceable master netting and/or similar arrangement. In addition, the revised guidance requires that certain enhanced quantitative and qualitative disclosures are made with respect to a company's netting arrangements and/or rights of offset associated with its financial instruments and/or derivative instruments. The revised disclosure guidance is effective on a retrospective basis for interim and annual periods beginning Jan. 1, 2013. The adoption of this standard will not have an impact on our financial position, results of operations or cash flows. Intangible - Goodwill and Other: Testing Indefinite Lived Intangible Assets for Impairment, ASU 2012-02 In July 2012, the FASB issued an amendment to accounting guidance for Intangibles - Goodwill and Other to provide an option to perform a qualitative assessment to determine whether further impairment testing of indefinite lived intangible assets is necessary. This ASU aligns the impairment testing for intangible assets with that of goodwill as amended by ASU 2011-08. This guidance is effective for interim and annual periods beginning after Sept. 15, 2012, with early adoption permitted. The adoption of this standard will not have an impact on our financial statements. Dodd-Frank Wall Street Reform and Consumer Protection Act, SEC Final Rule No. 34-67717 and No. 33-9338 In August 2012, the SEC approved a final rule implementing Section 1504 of Dodd-Frank. The rule requires issuers engaged in the commercial development of oil, natural gas or minerals to disclose cash payments made to a foreign government or the United States government. We are in the process of evaluating our reporting requirements. The adoption of this rule will not have an impact on our financial statements. Additionally, in July 2012, the CFTC and SEC published final rules that define “swap,” “security-based swap” and other key terms and concepts that are critical to the implementation of the derivatives reforms required by Dodd-Frank. We are in the process of evaluating our reporting requirements. The adoption of this rule will not have an impact on our financial position, results of operations or cash flows.

Supplemental Disclosure of Cash Flow Information

9 Months Ended

Sep. 30, 2012

Supplemental Disclosure of Cash Flow Information

SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION



	Nine Months Ended
	Sept. 30, 2012			Sept. 30, 2011
	(in thousands)
Non-cash investing activities from continuing operations—
Property, plant and equipment acquired with accounts payable and accrued liabilities	$	39,303		$	49,566
Capitalized assets associated with retirement obligations	$	3,806		$	—
Cash (paid) refunded during the period for continuing operations—
Interest (net of amounts capitalized)	$	(69,901	)	$	(60,934	)
Income taxes, net	$	425		$	11,939

Materials, Supplies and Fuel

9 Months Ended

Sep. 30, 2012

Inventory, Net [Abstract]

Materials, Supplies and Fuel

MATERIALS, SUPPLIES AND FUEL

The amounts of materials, supplies and fuel included in the accompanying Condensed Consolidated Balance Sheets, by major classification, were as follows (in thousands) as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
Materials and supplies	$	43,847	$	40,838	$	37,327
Fuel - Electric Utilities	8,289		8,201		8,639
Natural gas in storage held for distribution	28,764		35,025		38,641
Total materials, supplies and fuel	$	80,900	$	84,064	$	84,607

Accounts Receivable

9 Months Ended

Sep. 30, 2012

Receivables [Abstract]

Accounts Receivable

ACCOUNTS RECEIVABLE AND ALLOWANCE FOR DOUBTFUL ACCOUNTS

Accounts receivable consists primarily of customer trade accounts. The Gas Utilities' accounts receivable balance fluctuates primarily due to seasonality. We maintain an allowance for doubtful accounts that reflects our estimate of uncollectible trade receivables. We regularly review our trade receivable allowances by considering such factors as historical experience, credit worthiness, the age of the receivable balances and current economic conditions that may affect our ability to collect.

Following is a summary of receivables (in thousands) as of:



	Accounts		Unbilled		Less Allowance for			Accounts
Sept. 30, 2012	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	46,802	$	18,441	$	(603	)	$	64,640
Gas Utilities	18,198		9,480		(204		)	27,474
Oil and Gas	10,272		—		(105		)	10,167
Coal Mining	1,540		—		—			1,540
Power Generation	4		—		—			4
Corporate	657		—		—			657
Total	$	77,473	$	27,921	$	(912	)	$	104,482



	Accounts		Unbilled		Less Allowance for			Accounts
Dec. 31, 2011	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	42,773	$	21,151	$	(545	)	$	63,379
Gas Utilities	39,353		38,992		(1,011		)	77,334
Oil and Gas	11,282		—		(105		)	11,177
Coal Mining	4,056		—		—			4,056
Power Generation	282		—		—			282
Corporate	546		—		—			546
Total	$	98,292	$	60,143	$	(1,661	)	$	156,774



	Accounts		Unbilled		Less Allowance for			Accounts
Sept. 30, 2011	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	41,889	$	16,401	$	(590	)	$	57,700
Gas Utilities	21,168		12,518		(789		)	32,897
Oil and Gas	8,820		—		(161		)	8,659
Coal Mining	1,845		—		—			1,845
Power Generation	119		—		—			119
Corporate	1,453		—		—			1,453
Total	$	75,294	$	28,919	$	(1,540	)	$	102,673

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Publisher AICPA
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-Number 01-6
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Notes Payable

9 Months Ended

Sep. 30, 2012

Notes Payable [Abstract]

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

NOTES PAYABLE

Our credit facility and debt securities contain certain restrictive financial covenants. We were in compliance with all of these covenants at Sept. 30, 2012.

We had the following short-term debt outstanding at the Condensed Consolidated Balance Sheet dates (in thousands) as of:



	Sept. 30, 2012				Dec. 31, 2011				Sept. 30, 2011
	Notes Payable		Letters of Credit		Notes Payable		Letters of Credit		Notes Payable		Letters of Credit
Revolving Credit Facility	$	75,000	$	36,300	$	195,000	$	43,700	$	209,000	$	42,355
Term Loan due June 2013 ^(a)	150,000		—		150,000		—		150,000		—
Total	$	225,000	$	36,300	$	345,000	$	43,700	$	359,000	$	42,355

______________

(a) In June 2012, this short-term loan was extended for one year. See discussion below.

Revolving Credit Facility

On Feb. 1, 2012, we entered into a new $500 million Revolving Credit Facility expiring Feb. 1, 2017. The facility contains an accordion feature allowing us, with the consent of the administrative agent, to increase the capacity of the facility to $750 million. The Revolving Credit Facility can be used for the issuance of letters of credit, to fund working capital needs and for other corporate purposes. Borrowings are available under a base rate option or a Eurodollar option. The cost of borrowings or letters of credit is determined based upon our credit ratings. At current credit ratings, the margins for base rate borrowings, Eurodollar borrowings and letters of credit were 0.50 percent, 1.50 percent and 1.50 percent, respectively, at Sept. 30, 2012. The facility contains a commitment fee that is charged on the unused amount of the Revolving Credit Facility. Based upon current credit ratings, the fee is 0.25 percent.

Deferred financing costs on the Revolving Credit Facility of $2.8 million are being amortized over the estimated useful life of the Revolving Credit Facility and are included in Interest expense on the accompanying Condensed Consolidated Statements of Income. Upon entering into the Revolving Credit Facility, $1.5 million of deferred financing costs relating to the previous credit facility were written off through Interest expense.

Term Loans

On June 24, 2012, we extended the term of the $150 million term loan to June 24, 2013. The cost of borrowing is based on 1.10 percent over LIBOR.

Debt Covenants

Certain debt obligations require compliance with the following covenants at the end of each quarter (dollars in thousands):



	As of
	Sept. 30, 2012			Covenant Requirement
Consolidated Net Worth	$	1,214,317		Greater than	$	909,511
Recourse Leverage Ratio	56.3		%	Less than	65.0		%

Long-Term Debt	9 Months Ended
Long-Term Debt	Sep. 30, 2012
Long-term Debt, Unclassified [Abstract]
Long-term Debt [Text Block]	LONG TERM DEBT On May 15, 2012, Black Hills Power repaid its 4.8 percent Pollution Control Revenue Bonds in full for $6.5 million principal and interest. These bonds were originally due to mature on Oct. 1, 2014.

Earnings per Share

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

Earnings Per Share

EARNINGS PER SHARE

Basic Income (loss) per share from continuing operations is computed by dividing Income (loss) from continuing operations by the weighted-average number of common shares outstanding during the period. Diluted Income (loss) per share is computed by including all dilutive common shares potentially outstanding during a period.

A reconciliation of share amounts used to compute Income (loss) per share is as follows (in thousands):



	Three Months Ended Sept. 30,					Nine Months Ended Sept. 30,
	2012		2011			2012		2011

Income (loss) from continuing operations	$	34,623	$	(11,163	)	$	57,571	$	21,611

Weighted average shares - basic	43,847		39,145			43,792		39,105
Dilutive effect of:
Restricted stock	175		—			159		147
Stock options	12		—			14		16
Equity forward instruments	—		—			—		473
Other dilutive effects	74		—			61		51
Weighted average shares - diluted	44,108		39,145			44,026		39,792

Below is a discussion of our potentially dilutive shares that were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive.

Due to our net loss for the quarter ended Sept. 30, 2011, potentially dilutive securities, consisting of outstanding stock options, restricted common stock, restricted stock units, non-vested performance-based share awards and warrants, were excluded from the diluted loss per share calculation due to their anti-dilutive effect. In computing diluted net loss per share, 11,880 options to purchase shares of common stock, 159,873 vested and non-vested restricted stock shares, 31,408 warrants and other performance shares and 424,715 forward equity instruments were excluded from the computations for the three months ended Sept. 30, 2011.

In addition to these potentially dilutive shares excluded due to our net loss for third quarter of 2011, the following outstanding securities also were excluded in the computation of diluted Income (loss) per share from continuing operations as their inclusion would have been anti-dilutive (in thousands):



	Three Months Ended Sept. 30,		Nine Months Ended Sept. 30,
	2012	2011	2012	2011
Stock options	77	176	101	119
Restricted stock	61	20	53	17
Other stock	—	27	19	19
Anti-dilutive shares	138	223	173	155

Employee Benefit Plans

9 Months Ended

Sep. 30, 2012

Employee Benefit Plans

EMPLOYEE BENEFIT PLANS

Defined Benefit Pension Plans

We have three non-contributory defined benefit pension plans (Pension Plans). One covers certain eligible employees of Black Hills Service Company, Black Hills Power, WRDC and BHEP, one covers certain eligible employees of Cheyenne Light, and one covers certain eligible employees of Black Hills Energy. As of Jan. 1, 2012, all Pension Plans have been frozen to new employees and certain eligible employees who did not meet age and service based criteria at the time the Pension Plans were frozen. Additionally, effective Oct. 1, 2012, the Cheyenne Light Pension Plan was merged into the Black Hills Corporation Pension Plan. The Pension Plan benefits are based on years of service and compensation levels.

The components of net periodic benefit cost for the Pension Plans were as follows (in thousands):



	Three Months Ended Sept. 30,						Nine Months Ended Sept. 30,
	2012			2011			2012			2011
Service cost	$	1,431		$	1,355		$	4,291		$	4,066
Interest cost	3,688			3,732			11,062			11,196
Expected return on plan assets	(4,084		)	(4,239		)	(12,252		)	(12,717		)
Prior service cost	22			25			66			75
Net loss (gain)	2,408			1,135			7,224			3,405
Net periodic benefit cost	$	3,465		$	2,008		$	10,391		$	6,025

Non-pension Defined Benefit Postretirement Healthcare Plans

We sponsor the following retiree healthcare plans (Healthcare Plans): the Black Hills Corporation Postretirement Healthcare Plan, the Healthcare Plan for Retirees of Cheyenne Light, and the Black Hills Energy Postretirement Healthcare Plan. Employees who participate in the Healthcare Plans and who retire on or after meeting certain eligibility requirements are entitled to postretirement healthcare benefits.

The components of net periodic benefit cost for the Healthcare Plans were as follows (in thousands):



	Three Months Ended Sept. 30,						Nine Months Ended Sept. 30,
	2012			2011			2012			2011
Service cost	$	402		$	375		$	1,206		$	1,125
Interest cost	523			542			1,569			1,626
Expected return on plan assets	(19		)	(41		)	(57		)	(123		)
Prior service cost (benefit)	(125		)	(120		)	(375		)	(360		)
Net loss (gain)	222			169			666			507
Net periodic benefit cost	$	1,003		$	925		$	3,009		$	2,775

Supplemental Non-qualified Defined Benefit Plans

We have various supplemental retirement plans for key executives (Supplemental Plans). The Supplemental Plans are non-qualified defined benefit plans.

The components of net periodic benefit cost for the Supplemental Plans were as follows (in thousands):



	Three Months Ended Sept. 30,				Nine Months Ended Sept. 30,
	2012		2011		2012		2011
Service cost	$	243	$	257	$	735	$	771
Interest cost	331		324		993		973
Prior service cost	1		1		3		3
Net loss (gain)	202		128		606		383
Net periodic benefit cost	$	777	$	710	$	2,337	$	2,130

Contributions

We anticipate that we will make contributions to the benefit plans during 2012 and 2013. Contributions to the Pension Plans will be made in cash, and contributions to the Healthcare Plans and the Supplemental Plans are expected to be made in the form of benefit payments. Contributions and anticipated contributions are as follows (in thousands):



	Contributions Made		Contributions Made		Additional
	Three Months Ended Sept. 30, 2012		Nine Months Ended Sept. 30, 2012		Contributions Anticipated for 2012		Contributions Anticipated for 2013
Defined Benefit Pension Plans	$	—	$	25,000	$	—	$	4,500
Non-pension Defined Benefit Postretirement Healthcare Plans	$	1,063	$	3,189	$	1,063	$	4,380
Supplemental Non-qualified Defined Benefit Plans	$	278	$	834	$	278	$	1,090

The entire disclosure for pension and other postretirement benefits.

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-Number 30
-Paragraph 26
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Segment Reporting Information, Additional Information [Abstract]

Segment Reporting

9 Months Ended

Sep. 30, 2012

Summary of Information Relating to Segments of our Business

BUSINESS SEGMENT INFORMATION

Our reportable segments are based on our method of internal reporting, which generally segregates the strategic business groups due to differences in products, services and regulation. All of our operations and assets are located within the United States.

On Feb. 29, 2012, we sold our Energy Marketing segment, Enserco, which resulted in this segment being classified as discontinued operations. For comparative purposes, all prior periods presented have been restated to reflect the classification of this segment as discontinued operations. Indirect corporate costs and inter-segment interest expense related to Enserco that have not been classified as discontinued operations have been reclassified to our Corporate segment. For further information see Note 17.

We conduct our operations through the following five reportable segments:

Utilities Group —


•	Electric Utilities, which supplies electric utility service to areas in South Dakota, Wyoming, Colorado and Montana and natural gas utility service to Cheyenne, Wyo. and vicinity; and


•	Gas Utilities, which supplies natural gas utility service to areas in Colorado, Iowa, Kansas and Nebraska.

Non-regulated Energy Group —


•	Oil and Gas, which acquires, explores for, develops and produces crude oil and natural gas interests located in the Rocky Mountain region and other states;


•	Power Generation, which produces and sells power and capacity to wholesale customers from power plants located in Wyoming and Colorado; and


•	Coal Mining, which engages in the mining and sale of coal from our mine near Gillette, Wyo.

Segment information follows the accounting policies described in Note 1 of the Notes to Consolidated Financial Statements in our 2011 Annual Report on Form 10-K.

Segment information included in the accompanying Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets was as follows (in thousands):



Three Months Ended Sept. 30, 2012	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	151,281	$	3,736		$	14,573
Gas	63,435		—			3
Non-regulated Energy:
Oil and Gas ^(a)	24,728		—			17,389
Power Generation	1,256		19,695			5,128
Coal Mining	6,108		8,567			1,690
Corporate ^(b)	—		—			(4,160		)
Intercompany eliminations	—		(31,998		)	—
Total	$	246,808	$	—		$	34,623



Three Months Ended Sept. 30, 2011	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	151,063	$	2,653		$	15,790
Gas	72,651		—			572
Non-regulated Energy:
Oil and Gas	19,163		—			241
Power Generation	1,011		7,089			337
Coal Mining	9,184		8,651			555
Corporate ^(b)(c)	—		—			(28,307		)
Intercompany eliminations	—		(21,942		)	(351		)
Total	$	253,072	$	(3,549	)	$	(11,163	)



Nine Months Ended Sept. 30, 2012	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	451,974	$	11,946		$	37,478
Gas	314,343		—			16,369
Non-regulated Energy:
Oil and Gas ^(a)(d)	66,994		—			(2,219		)
Power Generation	3,193		56,119			15,968
Coal Mining	18,518		24,273			3,924
Corporate ^(b)	—		—			(13,949		)
Intercompany eliminations	—		(92,338		)	—
Total	$	855,022	$	—		$	57,571



Nine Months Ended Sept. 30, 2011	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	431,624	$	9,902		$	34,653
Gas	402,839		—			24,275
Non-regulated Energy:
Oil and Gas	55,907		—			(553		)
Power Generation	2,589		20,911			2,071
Coal Mining	23,064		25,806			(1,124		)
Corporate ^(b)(c)	—		—			(37,299		)
Intercompany eliminations	—		(61,635		)	(412		)
Total	$	916,023	$	(5,016	)	$	21,611

____________

Income Statement Notes:


(a)	Income (loss) from continuing operations includes a $17.7 million after-tax gain on the sale of the Williston Basin assets. See Note 15.

(b)

Income (loss) from continuing operations includes $0.4 million net after-tax non-cash mark-to-market gain and $1.9 million net after-tax non-cash mark-to-market loss on interest rate swaps for the three and nine months ended Sept. 30, 2012, respectively, and a $24.9 million and $26.4 million net after-tax non-cash mark-to-market loss on interest rate swaps for the three and nine months ended Sept. 30, 2011, respectively.


(c)	Certain indirect corporate costs and inter-segment interest expenses after-tax totaling $0.5 million for the three months ended Sept. 30, 2011 and $1.6 million and $1.5 million for the nine months ended Sept. 30, 2012 and 2011 were included in the Corporate segment in continuing operations and were not reclassified as discontinued operations. See Note 17 for further information.


(d)	Income (loss) from continuing operations includes a $17.3 million non-cash after-tax ceiling test impairment expense. See Note 16 for further information.



Total Assets (net of inter-company eliminations) as of:	Sept. 30, 2012		Dec. 31, 2011			Sept. 30, 2011
Utilities:
Electric^(a)	$	2,302,951	$	2,254,914		$	1,917,184
Gas	710,099		746,444			683,163
Non-regulated Energy:
Oil and Gas ^(b)	263,088		425,970			405,513
Power Generation^(a)	119,489		129,121			372,313
Coal Mining	90,444		88,704			94,908
Corporate	367,557		141,079		^(c)	139,985		^(c)
Discontinued operations	—		340,851		^(d)	332,503		^(d)
Total assets	$	3,853,628	$	4,127,083		$	3,945,569

____________


(a)	Upon commercial operation on Dec. 31, 2011 of the new generating facility constructed by Colorado IPP at our Pueblo Airport Generation site, the PPA under which energy and capacity is sold to Colorado Electric is accounted for as a capital lease. Therefore, commencing Dec. 31, 2011, assets previously recorded at Power Generation are now accounted for at Colorado Electric as a capital lease.


(b)	2012 includes a ceiling test impairment and the sale of the Williston Basin assets by our Oil and Gas segment. See Notes 15 and 16.


(c)	Assets of the Corporate segment were reclassified due to deferred taxes that were not classified as discontinued operations.


(d)	See Note 17 for further information relating to discontinued operations.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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Derivative Instruments and Hedging Activities Disclosure [Abstract]

Risk Management Activities

9 Months Ended

Sep. 30, 2012

Risk Management Activities

RISK MANAGEMENT ACTIVITIES

Our activities in the regulated and non-regulated energy sectors expose us to a number of risks in the normal operation of our businesses. Depending on the activity, we are exposed to varying degrees of market risk and credit risk. To manage and mitigate these identified risks, we have adopted the Black Hills Corporation Risk Policies and Procedures as discussed in our 2011 Annual Report on Form 10-K.

Market Risk

Market risk is the potential loss that might occur as a result of an adverse change in market price or rate. We are exposed to the following market risks including, but not limited to:


•	Commodity price risk associated with our natural long position with crude oil and natural gas reserves and production, fuel procurement for certain of our gas-fired generation assets and variability in revenue due to changes in gas usage at our regulated and non-regulated segments; and


•	Interest rate risk associated with our variable rate credit facility, project financing floating rate debt and our derivative instruments.

Our exposure to these market risks is affected by a number of factors including the size, duration, and composition of our energy portfolio, the absolute and relative levels of interest rates and commodity prices, the volatility of these prices and rates, and the liquidity of the related interest rate and commodity markets.

Credit Risk

Credit risk is the risk of financial loss resulting from non-performance of contractual obligations by a counterparty.

For production and generation activities, we attempt to mitigate our credit exposure by conducting business primarily with investment grade rated companies, setting tenor and credit limits commensurate with counterparty financial strength, obtaining master netting agreements, and mitigating credit exposure with less creditworthy counterparties through parental guarantees, prepayments, letters of credit, and other security agreements.

We perform ongoing credit evaluations of our customers and adjust credit limits based upon payment history and the customer's current creditworthiness, as determined by review of their current credit information. We maintain a provision for estimated credit losses based upon historical experience and any specific customer collection issue that is identified.

As of Sept. 30, 2012, our credit exposure (exclusive of retail customers of the regulated utilities) was concentrated primarily among investment grade rated companies, cooperative utilities and federal agencies.

We actively manage our exposure to certain market and credit risks as described in Note 3 of the Notes to the Consolidated Financial Statements in our 2011 Annual Report on Form 10-K. Our derivative and hedging activities included in the accompanying Condensed Consolidated Balance Sheets and Condensed Consolidated Statements of Income are detailed below and in Note 12.

Oil and Gas Exploration and Production

We produce natural gas and crude oil through our exploration and production activities. Our natural "long" positions, or unhedged open positions, result in commodity price risk and variability to our cash flows.

We hold a portfolio of swaps and options to hedge portions of our crude oil and natural gas production. We elect hedge accounting on those OTC swaps and options. These transactions were designated at inception as cash flow hedges, documented under accounting standards for derivatives and hedging, and initially met prospective effectiveness testing. Effectiveness of our hedging position is evaluated at least quarterly.

The derivatives are marked to fair value and are recorded as Derivative assets or Derivative liabilities on the accompanying Condensed Consolidated Balance Sheets. The effective portion of the gain or loss on these derivatives for which we have elected cash flow hedge accounting is reported in Accumulated other comprehensive income (loss) and the ineffective portion, if any, is reported in Revenue.

We had the following derivatives and related balances for our Oil and Gas segment (dollars in thousands) as of:



	Sept. 30, 2012					Dec. 31, 2011					Sept. 30, 2011
	Crude Oil Swaps/ Options		Natural Gas Swaps			Crude Oil Swaps/ Options			Natural Gas Swaps		Crude Oil Swaps/ Options		Natural Gas Swaps
Notional ^(a)	537,000		7,455,250			528,000			5,406,250		414,000		4,957,250
Maximum terms in years ^(b)	1.00		1.00			1.25			1.75		1.00		0.25
Derivative assets, current	$	1,651	$	2,032		$	729		$	8,010	$	1,885	$	6,937
Derivative assets, non-current	$	494	$	39		$	771		$	1,148	$	2,529	$	717
Derivative liabilities, current	$	527	$	1,040		$	2,559		$	—	$	—	$	—
Derivative liabilities, non-current	$	414	$	141		$	811		$	7	$	—	$	7
Pre-tax accumulated other comprehensive income (loss)	$	428	$	(344	)	$	(1,928	)	$	9,152	$	4,257	$	7,647
Cash collateral included in Derivative liabilities	$	—	$	—		$	—		$	—	$	—	$	—
Cash collateral included in Other current assets	$	1,126	$	1,288		$	—		$	—	$	—	$	—
Expense included in Revenue ^(c)	$	350	$	54		$	58		$	—	$	157	$	—

____________


(a)	Crude oil in Bbls, gas in MMBtus.


(b)	Refers to the term of the derivative instrument. Assets and liabilities are classified as current or non-current based on the term of the hedged transaction and the corresponding settlement of the derivative instruments.


(c)	Represents the amortization of put premiums.

Based on Sept. 30, 2012 market prices, a $1.2 million gain would be reclassified from AOCI during the next 12 months. Estimated and actual realized gains or losses will change during future periods as market prices fluctuate.

Utilities

Our utility customers are exposed to the effect of volatile natural gas prices; therefore, as allowed or required by state utility commissions, we have entered into certain natural gas futures, options and basis swaps to reduce our customers' underlying exposure to these fluctuations. These transactions are considered derivatives and in accordance with accounting standards for derivatives and hedging, mark-to-market adjustments are recorded as Derivative assets or Derivative liabilities on the accompanying Condensed Consolidated Balance Sheets. Gains and losses, as well as option premiums and commissions on these transactions are recorded as Regulatory assets or Regulatory liabilities in accordance with accounting standards for regulated utility operations. Accordingly, the hedging activity is recognized in the Condensed Consolidated Statements of Income when the related costs are recovered through our rates or adjustment mechanisms.

The contract notional amounts and terms of the natural gas derivative commodity instruments held at our Utilities were as follows as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
	Notional (MMBtus)	Maximum Term (months)	Notional (MMBtus)	Maximum Term (months)	Notional (MMBtus)	Maximum Term (months)
Natural gas futures purchased	14,690,000	75	14,310,000	84	9,890,000	18
Natural gas options purchased	5,560,000	6	1,720,000	3	3,880,000	6
Natural gas basis swaps purchased	8,800,000	75	7,160,000	60	—	—

We had the following derivative balances related to the hedges in our Utilities (in thousands) as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
Derivative assets, current	$	12,380	$	9,844	$	3,355
Derivative assets, non-current	$	634	$	52	$	—
Derivative liabilities, non-current	$	4,527	$	7,156	$	1,360
Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	9,318	$	17,556	$	11,813
Included in Derivatives:
Cash collateral receivable (payable)	$	15,740	$	19,416	$	12,058
Option premiums and commissions	$	2,065	$	880	$	1,750

Financing Activities

We have entered into floating-to-fixed interest rate swap agreements to reduce our exposure to interest rate fluctuations associated with our floating rate debt obligations. Our interest rate swaps and related balances were as follows (dollars in thousands) as of:



	Sept. 30, 2012						Dec. 31, 2011						Sept. 30, 2011
	Designated Interest Rate Swaps			De-designated Interest Rate Swaps*			Designated Interest Rate Swaps			De-designated Interest Rate Swaps*			Designated Interest Rate Swaps			De-designated Interest Rate Swaps*
Notional	$	150,000		$	250,000		$	150,000		$	250,000		$	150,000		$	250,000
Weighted average fixed interest rate	5.04		%	5.67		%	5.04		%	5.67		%	5.04		%	5.67		%
Maximum terms in years	4.25			1.25			5.00			2.00			5.25			0.25
Derivative liabilities, current	$	7,028		$	77,914		$	6,513		$	75,295		$	6,724		$	94,588
Derivative liabilities, non-current	$	18,660		$	17,668		$	20,363		$	20,696		$	21,108		$	—
Pre-tax accumulated other comprehensive income (loss)	$	(25,688	)	$	—		$	(26,876	)	$	—		$	(27,832	)	$	—
Year-to Date pre-tax gain (loss)	$	—		$	(2,902	)	$	—		$	(42,010	)	$	—		$	(40,608	)
Cash collateral receivable (payable) included in derivative	$	—		$	3,310		$	—		$	—		$	—		$	—

_____________


*	Maximum terms in years reflect the amended early termination dates. If the early termination dates are not extended, the swaps will require cash settlement based on the swap value on the termination date. If extended, de-designated swaps totaling $100 million notional terminate in 6.25 years and de-designated swaps totaling $150 million notional terminate in 16.25 years.

Collateral requirements based on our corporate credit rating apply to $50 million of our de-designated swaps. At our current credit ratings, we are required to post collateral for any amount by which the swaps' negative mark-to-market fair value exceeds $20 million. If our senior unsecured credit rating drops to BB+ or below by S&P, or to Ba1 or below by Moody's, we would be required to post collateral for the entire amount of the swaps' negative mark-to-market fair value.

Based on Sept. 30, 2012 market interest rates and balances related to our designated interest rate swaps, a loss of approximately $7.0 million would be reclassified from AOCI during the next 12 months. Estimated and actual realized gains or losses will change during future periods as market interest rates change.

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

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Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4E
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624181-113959

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]

Fair Value Measurements

9 Months Ended

Sep. 30, 2012

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Derivative Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The ASC on Fair Value Measurements and Disclosure Requirements establishes a hierarchy for grouping assets and liabilities, based on significance of inputs. For additional information see Notes 3 and 4 included in our 2011 Annual Report on Form 10-K filed with the SEC. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the placement within the fair value hierarchy levels. We record transfers, if necessary, between levels at the end of the reporting period for all of our financial instruments.

Transfers into Level 3, if any, occur when significant inputs used to value the derivative instruments become less observable such as a significant decrease in the frequency and volume in which the instrument is traded, negatively impacting the availability of observable pricing inputs. Transfers out of Level 3, if any, occur when the significant inputs become more observable such as the time between the valuation date and the delivery date of a transaction becomes shorter, positively impacting the availability of observable pricing inputs.

Valuation Methodologies

Oil and Gas Segment:


•	The commodity option contracts for the Oil and Gas segment are valued under the market approach and include calls and puts. Fair value was derived using quoted prices from third party brokers for similar instruments as to quantity and timing. The prices are then validated through multiple third party sources and therefore support Level 2 disclosure.


•	The commodity basis swaps for the Oil and Gas segment are valued under the market approach using the instrument's current forward price strip hedged for the same quantity and date and discounted based on the three-month LIBOR. We utilize observable inputs which support Level 2 disclosure.

Utilities Segment:

•

The commodity contracts for the Utilities, valued using the market approach, include exchange-traded futures, options and basis swaps (Level 2) and OTC basis swaps (Level 3) for natural gas contracts. For Level 2 assets and liabilities, fair value was derived using broker quotes validated by the Chicago Mercantile Exchange pricing for similar instruments. For Level 3 assets and liabilities, fair value was derived using average price quotes from the OTC contract broker and an independent third party market participant.

Corporate Segment:

•

The interest rate swaps are valued using the market valuation approach. We establish fair value by obtaining price quotes directly from the counterparty which are based on the floating three-month LIBOR curve for the term of the contract. The fair value obtained from the counterparty is then validated by utilizing a nationally recognized service that obtains observable inputs to compute fair value for the same instrument. In addition, the fair value for the interest rate swap derivatives includes a CVA component. The CVA considers the fair value of the interest rate swap and the probability of default based on the life of the contract. For the probability of a default component, we utilize observable inputs supporting Level 2 disclosure by using our credit default spread, if available, or a generic credit default spread curve that takes into account our credit ratings.

Recurring Fair Value Measurements

There have been no significant transfers between Level 1 and Level 2 derivative balances. The following tables set forth by level within the fair value hierarchy our assets and liabilities that were accounted for at fair value on a recurring basis (in thousands):



	As of Sept. 30, 2012
	Level 1		Level 2			Level 3			Counterparty Netting		Cash Collateral			Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	619		$	—		$	—	$	—		$	619
Basis Swaps -- Oil	—		1,526			—			—		—			1,526
Options -- Gas	—		—			—			—		—			—
Basis Swaps -- Gas	—		2,071			—			—		—			2,071
Commodity derivatives — Utilities	—		(2,760		)	34		^(b)	—		15,740			13,014
Cash and cash equivalents ^(a)	247,192		—			—			—		—			247,192
Total	$	247,192	$	1,456		$	34		$	—	$	15,740		$	264,422

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	885		$	—		$	—	$	—		$	885
Basis Swaps -- Oil	—		56			—			—		—			56
Options -- Gas	—		—			—			—		—			—
Basis Swaps -- Gas	—		1,181			—			—		—			1,181
Commodity derivatives — Utilities	—		4,527			—			—		—			4,527
Interest rate swaps	—		124,580			—			—		(3,310		)	121,270
Total	$	—	$	131,229		$	—		$	—	$	(3,310	)	$	127,919

______________


(a)	Level 1 assets and liabilities are described in Note 13.

(b)

The significant unobservable inputs used in the fair value measurement of the long-term OTC contracts are based on the average of price quotes from an independent third party market participant and the OTC contract broker. The unobservable inputs are long-term natural gas prices. Significant changes to these inputs along with the contract term would impact the derivative asset/liability and regulatory asset/liability, but will not impact the results of operations until the contract is settled under the original terms of the contract. The contracts will be classified as Level 2 once settlement is within 60 months of maturity and quoted market prices from a market exchange are available.



	As of Dec. 31, 2011
	Level 1		Level 2			Level 3			Counterparty Netting		Cash Collateral		Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	768	^(a)	$	5	$	—	$	773
Basis Swaps -- Oil	—		727			—			—		—		727
Options -- Gas	—		—			—			—		—		—
Basis Swaps -- Gas	—		9,158			—			—		—		9,158
Commodity derivatives —Utilities	—		(9,520		)	—			—		19,416		9,896
Money market funds	6,005		—			—			—		—		6,005
Total	$	6,005	$	365		$	768	^(a)	$	5	$	19,416	$	26,559

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	1,165	^(a)	$	5	$	—	$	1,170
Basis Swaps -- Oil	—		2,200			—			—		—		2,200
Options -- Gas	—		—			—			—		—		—
Basis Swaps -- Gas	—		7			—			—		—		7
Commodity derivatives — Utilities	—		7,156			—			—		—		7,156
Interest rate swaps	—		122,867			—			—		—		122,867
Total	$	—	$	132,230		$	1,165	^(a)	$	5	$	—	$	133,400

_________


(a)	Of the net balance included as Level 3, transfers out of Level 3 included settlement of losses of approximately $0.5 million within AOCI and approximately $0.9 million transferred to level 2 as inputs becoming more observable.



	As of Sept. 30, 2011
	Level 1		Level 2			Level 3		Counterparty Netting		Cash Collateral		Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	328	$	—	$	—	$	328
Basis Swaps -- Oil	—		4,086			—		—		—		4,086
Options -- Gas	—		—			—		—		—		—
Basis Swaps -- Gas	—		7,654			—		—		—		7,654
Commodity derivatives — Utilities	—		(8,703		)	—		—		12,058		3,355
Money market funds	9,006		—			—		—		—		9,006
Total	$	9,006	$	3,037		$	328	$	—	$	12,058	$	24,429

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	—	$	—	$	—	$	—
Basis Swaps -- Oil	—		—			—		—		—		—
Options -- Gas	—		—			—		—		—		—
Basis Swaps -- Gas	—		7			—		—		—		7
Commodity derivatives — Utilities	—		1,360			—		—		—		1,360
Interest rate swaps	—		122,420			—		—		—		122,420
Total	$	—	$	123,787		$	—	$	—	$	—	$	123,787

Fair Value Measures

As required by accounting standards for derivatives and hedges, fair values within the following tables are presented on a gross basis and do not reflect the netting of asset and liability positions permitted in accordance with accounting standards for offsetting and under terms of our master netting agreements. Further, the amounts do not include net cash collateral on deposit in margin accounts at Sept. 30, 2012, Dec. 31, 2011, and Sept. 30, 2011, to collateralize certain financial instruments, which are included in Derivative assets and/or Derivative liabilities. Therefore, the gross balances are not indicative of either our actual credit exposure or net economic exposure. Additionally, the amounts below will not agree with the amounts presented on our Condensed Consolidated Balance Sheets, nor will they correspond to the fair value measurements presented in Note 11.

The following tables present the fair value and balance sheet classification of our derivative instruments (in thousands):



As of Sept. 30, 2012
	Balance Sheet Location	Fair Value of Asset Derivatives		Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	3,263	$	—
Commodity derivatives	Derivative assets — non-current	533		—
Commodity derivatives	Derivative liabilities — current	—		1,534
Commodity derivatives	Derivative liabilities — non-current	—		555
Interest rate swaps	Derivative liabilities — current	—		7,029
Interest rate swaps	Derivative liabilities — non-current	—		18,661
Total derivatives designated as hedges		$	3,796	$	27,779

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	421	$	3,361
Commodity derivatives	Derivative assets — non-current	—		(634		)
Commodity derivatives	Derivative liabilities — current	—		33
Commodity derivatives	Derivative liabilities — non-current	—		4,527
Interest rate swaps	Derivative liabilities — current	—		77,913
Interest rate swaps	Derivative liabilities — non-current	—		20,977
Total derivatives not designated as hedges		$	421	$	106,177



As of Dec. 31, 2011
	Balance Sheet Location	Fair Value of Asset Derivatives		Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	8,739	$	—
Commodity derivatives	Derivative assets — non-current	1,919		—
Commodity derivatives	Derivative liabilities — current	—		2,559
Commodity derivatives	Derivative liabilities — non-current	—		818
Interest rate swaps	Derivative liabilities — current	—		6,513
Interest rate swaps	Derivative liabilities — non-current	—		20,363
Total derivatives designated as hedges		$	10,658	$	30,253

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	—	$	9,572
Commodity derivatives	Derivative assets — non-current	—		(52		)
Commodity derivatives	Derivative liabilities — current	—		—
Commodity derivatives	Derivative liabilities — non-current	—		7,156
Interest rate swaps	Derivative liabilities — current	—		75,295
Interest rate swaps	Derivative liabilities — non-current	—		20,696
Total derivatives not designated as hedges		$	—	$	112,667



As of Sept. 30, 2011
	Balance Sheet Location	Fair Value of Asset Derivatives			Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	8,822		$	—
Commodity derivatives	Derivative assets — non-current	3,246			—
Commodity derivatives	Derivative liabilities — current	—			—
Commodity derivatives	Derivative liabilities — non-current	—			7
Interest rate swaps	Derivative liabilities — current	—			6,724
Interest rate swaps	Derivative liabilities — non-current	—			21,108
Total derivatives designated as hedges		$	12,068		$	27,839

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	—		$	8,703
Commodity derivatives	Derivative assets — non-current	—			—
Commodity derivatives	Derivative liabilities — current	(2		)	(1,360		)
Commodity derivatives	Derivative liabilities — non-current	—			—
Interest rate swaps	Derivative liabilities — current	—			94,588
Interest rate swaps	Derivative liabilities — non-current	—			—
Total derivatives not designated as hedges		$	(2	)	$	101,931

A description of our derivative activities is included in Note 11. The following tables present the impact that derivatives had on our Condensed Consolidated Statements of Income.

Cash Flow Hedges

The impact of cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):



Three Months Ended Sept. 30, 2012
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(1,684	)	Interest expense	$	(1,853	)		$	—
Commodity derivatives	(3,111		)	Revenue	1,838				—
Total	$	(4,795	)		$	(15	)		$	—



Three Months Ended Sept. 30, 2011
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(6,958	)	Interest expense	$	(1,930	)		$	—
Commodity derivatives	10,095			Revenue	1,516				—
Total	$	3,137			$	(414	)		$	—



Nine Months Ended Sept. 30, 2012
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(4,697	)	Interest expense	$	(5,518	)		$	—
Commodity derivatives	601			Revenue	7,741				—
Total	$	(4,096	)		$	2,223			$	—



Nine Months Ended Sept. 30, 2011
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(11,428	)	Interest expense	$	(5,741	)		$	—
Commodity derivatives	9,784			Revenue	2,849				—
Total	$	(1,644	)		$	(2,892	)		$	—

Derivatives Not Designated as Hedge Instruments

The impact of derivative instruments that have not been designated as hedging instruments on our Condensed Consolidated Statements of Income was as follows (in thousands):



		Three Months Ended			Nine Months Ended
		Sept. 30, 2012			Sept. 30, 2012
Derivatives Not Designated as Hedging Instruments	Location of Gain/(Loss) on Derivatives Recognized in Income	Amount of Gain/(Loss) on Derivatives Recognized in Income			Amount of Gain/(Loss) on Derivatives Recognized in Income
Interest rate swaps - unrealized	Unrealized gain (loss) on interest rate swaps, net	$	605		$	(2,902	)
Interest rate swaps - realized	Interest expense	(3,250		)	(9,697		)
Commodity derivatives	Revenue	(14		)	(14		)
		$	(2,659	)	$	(12,613	)



		Three Months Ended			Nine Months Ended
		Sept. 30, 2011			Sept. 30, 2011
Derivatives Not Designated as Hedging Instruments	Location of Gain/(Loss) on Derivatives Recognized in Income	Amount of Gain/(Loss) on Derivatives Recognized in Income			Amount of Gain/(Loss) on Derivatives Recognized in Income
Interest rate swaps - unrealized	Unrealized gain (loss) on interest rate swaps, net	$	(38,246	)	$	(40,608	)
Interest rate swaps - realized	Interest expense	(3,373		)	(10,077		)
		$	(41,619	)	$	(50,685	)

Fair Value of Financial Instruments

9 Months Ended

Sep. 30, 2012

Fair Value of Financial Instruments

FAIR VALUE OF FINANCIAL INSTRUMENTS

The estimated fair values of our financial instruments are as follows (in thousands) as of:



	Sept. 30, 2012				Dec. 31, 2011				Sept. 30, 2011
	Carrying Amount		Fair Value		Carrying Amount		Fair Value		Carrying Amount		Fair Value
Cash and cash equivalents ^(a)	$	247,192	$	247,192	$	21,628	$	21,628	$	30,198	$	30,198
Restricted cash and equivalents ^(a)	$	7,302	$	7,302	$	9,254	$	9,254	$	4,080	$	4,080
Notes receivable ^(a)	$	21,832	$	21,832	$	—	$	—	$	—	$	—
Notes payable ^(b)	$	225,000	$	225,000	$	345,000	$	345,000	$	359,000	$	359,000
Long-term debt, including current maturities ^(c)	$	1,271,260	$	1,471,932	$	1,282,882	$	1,464,289	$	1,285,087	$	1,430,271

____________


(a)	Fair value approximates carrying value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates and therefore is classified in Level 1 in the fair value hierarchy.


(b)	The carrying amounts of our notes payable approximate fair value due to their variable interest rates with short reset periods.


(c)	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

The following methods and assumptions were used to estimate the fair value of each class of our financial instruments.

Cash and Cash Equivalents

Included in cash and cash equivalents are cash, overnight repurchase agreement accounts, money market funds and term deposits. As part of our cash management process, excess operating cash is invested in overnight repurchase agreements with our bank. Repurchase agreements are not deposits and are not insured by the U.S. Government, the FDIC or any other government agency and involve investment risk including possible loss of principal. We believe, however, that the market risk arising from holding these financial instruments is minimal.

Restricted Cash and Equivalents

Restricted cash and equivalents represent restricted cash and uninsured term deposits.

Notes Receivable

Notes receivable, included in Other current assets on the accompanying Condensed Consolidated Balance Sheet, represents cash held by a third party related to tax planning strategies for effecting like-kind exchange structuring for the purchase of additional oil and gas leases.

Notes Payable

Notes Payable represent our short-term corporate term loan and borrowings under our Revolving Credit Facility.

Long-term Debt

Our debt instruments are marked to fair value using the market valuation approach. The fair value for our fixed rate debt instruments is estimated based on quoted market prices and yields for debt instruments having similar maturities and debt ratings. The carrying amounts of our variable rate debt approximate fair value due to the variable interest rates with short reset periods.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-Section 50
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

9 Months Ended

Sep. 30, 2012

Commitments and Contingencies

COMMITMENTS AND CONTINGENCIES

Commitments and Contingencies

There have been no significant changes to commitments and contingencies from those previously disclosed in Note 19 of our Notes to the Consolidated Financial Statements in our 2011 Annual Report on Form 10-K.

Dividend Restrictions

Our Revolving Credit Facility and other debt obligations contain restrictions on the payment of cash dividends upon a default or event of default. As of Sept. 30, 2012, we were in compliance with these covenants.

Due to our holding company structure, substantially all of our operating cash flows are provided by dividends paid or distributions made by our subsidiaries. The cash to pay dividends to our stockholders is derived from these cash flows. As a result, certain statutory limitations or regulatory or financing agreements could affect the levels of distributions allowed to be made by our subsidiaries. The following restrictions on distributions from our subsidiaries existed at Sept. 30, 2012:


•	Our utilities are generally limited to the amount of dividends allowed to be paid to us as a utility holding company under the Federal Power Act and settlement agreements with state regulatory jurisdictions. As of Sept. 30, 2012, the restricted net assets at our Utilities Group were approximately $227.2 million.


•	As required by the covenant in the Black Hills Wyoming project financing, Black Hills Non-regulated Holdings has maintained restricted equity of at least $100.0 million.

The entire disclosure for commitments and contingencies.

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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Name FASB Interpretation (FIN)
-Number 14
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Property Plant And Equipment Significant Disposals [Text Block]

Sale of Assets

9 Months Ended

Sep. 30, 2012

Sale of Operating Assets [Abstract]

SALE OF ASSETS

Oil and Gas

On Sept. 27, 2012, our Oil and Gas segment sold a majority of its Bakken and Three Forks shale assets in the Williston Basin of North Dakota. The sale included approximately 73 gross wells, 28,000 net lease acres and had an effective date of July 1, 2012.

Our Oil and Gas segment follows the full-cost method of accounting for oil and gas activities. Typically this methodology does not allow for gain or loss on sale and proceeds from sale are credited against the full cost pool. Gain or loss recognition is allowed when such adjustments would significantly alter the relationship between capitalized costs and proved reserves of oil and gas attributable to a cost center. The Sept. 27, 2012 sale significantly alters the relationship and accordingly we have recorded a gain of $27.3 million with the remainder of the proceeds recorded as a reduction in the full cost pool. This reduction in the full cost pool will decrease in the depreciation, depletion and amortization rate.

Net cash proceeds were as follows (in thousands):



Cash proceeds received on date of sale	$	243,314

Adjustments to proceeds:
Post close adjustments	1,490
Transaction adviser fees	(1,400		)
Estimated payment for contractual obligation related to "back-in" fee *	(16,847		)

Net cash proceeds	$	226,557

_____________

* Required payment, triggered by the sale of the property, arising from a contractual obligation contained in the original participation agreement with the property operator.

Electric Utilities

On Sept. 18, 2012, Colorado Electric completed the sale of an undivided 50 percent ownership interest in the 29 megawatt Busch Ranch Wind project to AltaGas for $25.0 million. Colorado Electric retains the remaining undivided interest and will be the operator of this jointly owned facility. Commercial operation of the newly constructed wind farm was achieved on Oct. 16, 2012. Colorado Electric will purchase AltaGas's interest in the energy produced by the wind farm through a REPA expiring on Oct. 16, 2037.

Impairment of Long-lived Assets	9 Months Ended
Impairment of Long-lived Assets	Sep. 30, 2012
Impairment of Long-lived Assets [Abstract]
Asset Impairment Charges [Text Block]	IMPAIRMENT OF LONG-LIVED ASSETS Under the full cost method of accounting used by our Oil and Gas segment to account for exploration, development, and acquisition of crude oil and natural gas reserves, all costs attributable to these activities are capitalized. These capitalized costs, less accumulated amortization and related deferred income taxes, are subject to a ceiling test that limits the pooled costs to the aggregate of the discounted value of future net revenue attributable to proved natural gas and crude oil reserves using a discount rate defined by the SEC plus the lower of cost or market value of unevaluated properties. Any costs in excess of the ceiling are written off as a non-cash charge. As a result of continued low commodity prices, we recorded a $26.9 million non-cash impairment of oil and gas assets included in our Oil and Gas segment in the second quarter of 2012. In determining the ceiling value of our assets, we utilized the average of the quoted prices from the first day of each month from the previous 12 months. For natural gas, the average NYMEX price was $3.15 per Mcf, adjusted to $2.66 per Mcf at the wellhead; for crude oil, the average NYMEX price was $95.67 per barrel, adjusted to $85.36 per barrel at the wellhead.

Discontinued Operations

9 Months Ended

Sep. 30, 2012

Discontinued Operations and Disposal Groups [Abstract]

Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]

DISCONTINUED OPERATIONS

On Feb. 29, 2012, we sold the outstanding stock of Enserco, our Energy Marketing segment. The transaction was completed through a stock purchase agreement and certain other ancillary agreements. Net cash proceeds on the date of the sale were approximately $166.3 million, subject to final post-closing adjustments. The proceeds represent $108.8 million received from the buyer and $57.5 million cash retained from Enserco prior to closing.

Pursuant to the provisions of the stock purchase agreement, the buyer requested purchase price adjustments totaling $7.2 million. We contested this proposed adjustment and estimated the amount owed at $1.4 million, which is accrued for in the accompanying financial statements as of Sept. 30, 2012. If we do not reach a negotiated agreement with the buyer regarding the purchase price adjustment, resolution will occur through the dispute resolution provision of the stock purchase agreement.

The accompanying Condensed Consolidated Financial Statements have been classified to reflect Enserco as discontinued operations. For comparative purposes, all prior periods presented have been restated to reflect the classification.

Operating results of the Energy Marketing segment included in Income (loss) from discontinued operations, net of tax on the accompanying Condensed Consolidated Statements of Income were as follows (in thousands):



	For the Three Months Ended						For the Nine Months Ended
	Sept. 30, 2012			Sept. 30, 2011			Sept. 30, 2012			Sept. 30, 2011

Revenue	$	—		$	6,937		$	(604	)	$	21,878

Pre-tax income (loss) from discontinued operations	$	(311	)	$	1,495		$	(6,622	)	$	4,404
Pre-tax gain (loss) on sale	—			—			(3,787		)	—
Income tax (expense) benefit	145			(857		)	3,599			(1,878		)

Income (loss) from discontinued operations, net of tax ^(a)	$	(166	)	$	638		$	(6,810	)	$	2,526

_____________


(a)	Includes transaction related costs, net of tax, of $0.2 million and $2.5 million for three and nine months ended Sept. 30, 2012, respectively.

Indirect corporate costs and inter-segment interest expense after-tax totaling $0.5 million for the three months ended Sept. 30, 2011, and $1.6 million and $1.5 million for the nine months ended Sept. 30, 2012 and 2011, respectively, were reclassified from the Energy Marketing segment to the Corporate segment in continuing operations on the accompanying Condensed Consolidated Statements of Income.

Net assets of the Energy Marketing segment included in Assets/Liabilities of discontinued operations in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands) as of:



	Dec. 31, 2011			Sept. 30, 2011

Other current assets	$	280,221		$	282,361
Derivative assets, current and non-current	52,859			50,519
Property, plant and equipment, net	5,828			5,391
Goodwill	1,435			1,435
Other non-current assets	508			(7,204		)
Other current liabilities	(132,951		)	(134,747		)
Derivative liabilities, current and non-current	(26,084		)	(31,978		)
Other non-current liabilities	(14,894		)	(4,959		)
Net assets	$	166,922		$	160,818

The entire disclosure for the facts and circumstances leading to the completed or expected disposal, manner and timing of disposal, the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the segment in which the disposal group was reported, and the classification (whether sold or classified as held for sale) and carrying value of the assets and liabilities comprising the disposal group. Includes all disposal groups, including those classified as components of the entity (discontinued operations).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 43-48
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Supplemental Cash Flow Information [Abstract]

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2012
Subsequent Events [Abstract]
Subsequent Event	SUBSEQUENT EVENTS Long-term Debt On Oct. 31, 2012, we redeemed our $225.0 million of senior unsecured 6.5 percent notes, which were originally scheduled to mature on May 15, 2013. The total payment was $238.8 million, including accrued interest expense and a make-whole provision payment of $7.1 million.

Supplemental Disclosure of Cash Flow Information Suplemental Disclosures of Cash Flow Information (Tables)

9 Months Ended

Sep. 30, 2012

Supplemental Disclosure of Cash Flow Information



	Nine Months Ended
	Sept. 30, 2012			Sept. 30, 2011
	(in thousands)
Non-cash investing activities from continuing operations—
Property, plant and equipment acquired with accounts payable and accrued liabilities	$	39,303		$	49,566
Capitalized assets associated with retirement obligations	$	3,806		$	—
Cash (paid) refunded during the period for continuing operations—
Interest (net of amounts capitalized)	$	(69,901	)	$	(60,934	)
Income taxes, net	$	425		$	11,939

Materials, Supplies and Fuel Materials, Supplies and Fuel (Tables)

9 Months Ended

Sep. 30, 2012

Inventory, Net [Abstract]

Schedule of Inventory, current

The amounts of materials, supplies and fuel included in the accompanying Condensed Consolidated Balance Sheets, by major classification, were as follows (in thousands) as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
Materials and supplies	$	43,847	$	40,838	$	37,327
Fuel - Electric Utilities	8,289		8,201		8,639
Natural gas in storage held for distribution	28,764		35,025		38,641
Total materials, supplies and fuel	$	80,900	$	84,064	$	84,607

Accounts Receivable Accounts Receivable (Tables)

9 Months Ended

Sep. 30, 2012

Receivables [Abstract]

Summary of accounts receivables

Following is a summary of receivables (in thousands) as of:



	Accounts		Unbilled		Less Allowance for			Accounts
Sept. 30, 2012	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	46,802	$	18,441	$	(603	)	$	64,640
Gas Utilities	18,198		9,480		(204		)	27,474
Oil and Gas	10,272		—		(105		)	10,167
Coal Mining	1,540		—		—			1,540
Power Generation	4		—		—			4
Corporate	657		—		—			657
Total	$	77,473	$	27,921	$	(912	)	$	104,482



	Accounts		Unbilled		Less Allowance for			Accounts
Dec. 31, 2011	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	42,773	$	21,151	$	(545	)	$	63,379
Gas Utilities	39,353		38,992		(1,011		)	77,334
Oil and Gas	11,282		—		(105		)	11,177
Coal Mining	4,056		—		—			4,056
Power Generation	282		—		—			282
Corporate	546		—		—			546
Total	$	98,292	$	60,143	$	(1,661	)	$	156,774



	Accounts		Unbilled		Less Allowance for			Accounts
Sept. 30, 2011	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
Electric Utilities	$	41,889	$	16,401	$	(590	)	$	57,700
Gas Utilities	21,168		12,518		(789		)	32,897
Oil and Gas	8,820		—		(161		)	8,659
Coal Mining	1,845		—		—			1,845
Power Generation	119		—		—			119
Corporate	1,453		—		—			1,453
Total	$	75,294	$	28,919	$	(1,540	)	$	102,673

Notes Payable Notes Payable (Tables)

9 Months Ended

Sep. 30, 2012

Schedule of Short-term Debt

We had the following short-term debt outstanding at the Condensed Consolidated Balance Sheet dates (in thousands) as of:



	Sept. 30, 2012				Dec. 31, 2011				Sept. 30, 2011
	Notes Payable		Letters of Credit		Notes Payable		Letters of Credit		Notes Payable		Letters of Credit
Revolving Credit Facility	$	75,000	$	36,300	$	195,000	$	43,700	$	209,000	$	42,355
Term Loan due June 2013 ^(a)	150,000		—		150,000		—		150,000		—
Total	$	225,000	$	36,300	$	345,000	$	43,700	$	359,000	$	42,355

______________

(a) In June 2012, this short-term loan was extended for one year. See discussion below.

Revolving Credit Facility, Existing [Member]

Credit Facility Covenants

Certain debt obligations require compliance with the following covenants at the end of each quarter (dollars in thousands):



	As of
	Sept. 30, 2012			Covenant Requirement
Consolidated Net Worth	$	1,214,317		Greater than	$	909,511
Recourse Leverage Ratio	56.3		%	Less than	65.0		%

Earnings per Share Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

Earnings Per Share Reconciliation

A reconciliation of share amounts used to compute Income (loss) per share is as follows (in thousands):



	Three Months Ended Sept. 30,					Nine Months Ended Sept. 30,
	2012		2011			2012		2011

Income (loss) from continuing operations	$	34,623	$	(11,163	)	$	57,571	$	21,611

Weighted average shares - basic	43,847		39,145			43,792		39,105
Dilutive effect of:
Restricted stock	175		—			159		147
Stock options	12		—			14		16
Equity forward instruments	—		—			—		473
Other dilutive effects	74		—			61		51
Weighted average shares - diluted	44,108		39,145			44,026		39,792

Antidilutive Securities Excluded from Computation of Earnings Per Share

the following outstanding securities also were excluded in the computation of diluted Income (loss) per share from continuing operations as their inclusion would have been anti-dilutive (in thousands):



	Three Months Ended Sept. 30,		Nine Months Ended Sept. 30,
	2012	2011	2012	2011
Stock options	77	176	101	119
Restricted stock	61	20	53	17
Other stock	—	27	19	19
Anti-dilutive shares	138	223	173	155

Employee Benefit Plans Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2012

Contributions to Healthcare and Supplemental Plans

Contributions to the Pension Plans will be made in cash, and contributions to the Healthcare Plans and the Supplemental Plans are expected to be made in the form of benefit payments. Contributions and anticipated contributions are as follows (in thousands):



	Contributions Made		Contributions Made		Additional
	Three Months Ended Sept. 30, 2012		Nine Months Ended Sept. 30, 2012		Contributions Anticipated for 2012		Contributions Anticipated for 2013
Defined Benefit Pension Plans	$	—	$	25,000	$	—	$	4,500
Non-pension Defined Benefit Postretirement Healthcare Plans	$	1,063	$	3,189	$	1,063	$	4,380
Supplemental Non-qualified Defined Benefit Plans	$	278	$	834	$	278	$	1,090

Pension Plans, Defined Benefit [Member]

Components of net periodic benefit cost

The components of net periodic benefit cost for the Pension Plans were as follows (in thousands):



	Three Months Ended Sept. 30,						Nine Months Ended Sept. 30,
	2012			2011			2012			2011
Service cost	$	1,431		$	1,355		$	4,291		$	4,066
Interest cost	3,688			3,732			11,062			11,196
Expected return on plan assets	(4,084		)	(4,239		)	(12,252		)	(12,717		)
Prior service cost	22			25			66			75
Net loss (gain)	2,408			1,135			7,224			3,405
Net periodic benefit cost	$	3,465		$	2,008		$	10,391		$	6,025

Non-pension Postretirement Healthcare Plans, Defined Benefit [Member]

Components of net periodic benefit cost

The components of net periodic benefit cost for the Healthcare Plans were as follows (in thousands):



	Three Months Ended Sept. 30,						Nine Months Ended Sept. 30,
	2012			2011			2012			2011
Service cost	$	402		$	375		$	1,206		$	1,125
Interest cost	523			542			1,569			1,626
Expected return on plan assets	(19		)	(41		)	(57		)	(123		)
Prior service cost (benefit)	(125		)	(120		)	(375		)	(360		)
Net loss (gain)	222			169			666			507
Net periodic benefit cost	$	1,003		$	925		$	3,009		$	2,775

Supplemental Non-qualified Plans, Defined Benefit [Member]

Components of net periodic benefit cost

The components of net periodic benefit cost for the Supplemental Plans were as follows (in thousands):



	Three Months Ended Sept. 30,				Nine Months Ended Sept. 30,
	2012		2011		2012		2011
Service cost	$	243	$	257	$	735	$	771
Interest cost	331		324		993		973
Prior service cost	1		1		3		3
Net loss (gain)	202		128		606		383
Net periodic benefit cost	$	777	$	710	$	2,337	$	2,130

Segment Reporting Segment Reporting (Tables)

9 Months Ended

Sep. 30, 2012

Segment Reporting Information, Additional Information [Abstract]

Segment information included in Condensed Consolidated Statements of Income

Segment information included in the accompanying Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets was as follows (in thousands):



Three Months Ended Sept. 30, 2012	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	151,281	$	3,736		$	14,573
Gas	63,435		—			3
Non-regulated Energy:
Oil and Gas ^(a)	24,728		—			17,389
Power Generation	1,256		19,695			5,128
Coal Mining	6,108		8,567			1,690
Corporate ^(b)	—		—			(4,160		)
Intercompany eliminations	—		(31,998		)	—
Total	$	246,808	$	—		$	34,623



Three Months Ended Sept. 30, 2011	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	151,063	$	2,653		$	15,790
Gas	72,651		—			572
Non-regulated Energy:
Oil and Gas	19,163		—			241
Power Generation	1,011		7,089			337
Coal Mining	9,184		8,651			555
Corporate ^(b)(c)	—		—			(28,307		)
Intercompany eliminations	—		(21,942		)	(351		)
Total	$	253,072	$	(3,549	)	$	(11,163	)



Nine Months Ended Sept. 30, 2012	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	451,974	$	11,946		$	37,478
Gas	314,343		—			16,369
Non-regulated Energy:
Oil and Gas ^(a)(d)	66,994		—			(2,219		)
Power Generation	3,193		56,119			15,968
Coal Mining	18,518		24,273			3,924
Corporate ^(b)	—		—			(13,949		)
Intercompany eliminations	—		(92,338		)	—
Total	$	855,022	$	—		$	57,571



Nine Months Ended Sept. 30, 2011	External Operating Revenues		Intercompany Operating Revenues			Income (Loss) from Continuing Operations
Utilities:
Electric	$	431,624	$	9,902		$	34,653
Gas	402,839		—			24,275
Non-regulated Energy:
Oil and Gas	55,907		—			(553		)
Power Generation	2,589		20,911			2,071
Coal Mining	23,064		25,806			(1,124		)
Corporate ^(b)(c)	—		—			(37,299		)
Intercompany eliminations	—		(61,635		)	(412		)
Total	$	916,023	$	(5,016	)	$	21,611

____________

Income Statement Notes:


(a)	Income (loss) from continuing operations includes a $17.7 million after-tax gain on the sale of the Williston Basin assets. See Note 15.

(b)


(c)	Certain indirect corporate costs and inter-segment interest expenses after-tax totaling $0.5 million for the three months ended Sept. 30, 2011 and $1.6 million and $1.5 million for the nine months ended Sept. 30, 2012 and 2011 were included in the Corporate segment in continuing operations and were not reclassified as discontinued operations. See Note 17 for further information.


(d)	Income (loss) from continuing operations includes a $17.3 million non-cash after-tax ceiling test impairment expense. See Note 16 for further information.

Segment information included in Condensed Consolidated Balance Sheets



Total Assets (net of inter-company eliminations) as of:	Sept. 30, 2012		Dec. 31, 2011			Sept. 30, 2011
Utilities:
Electric^(a)	$	2,302,951	$	2,254,914		$	1,917,184
Gas	710,099		746,444			683,163
Non-regulated Energy:
Oil and Gas ^(b)	263,088		425,970			405,513
Power Generation^(a)	119,489		129,121			372,313
Coal Mining	90,444		88,704			94,908
Corporate	367,557		141,079		^(c)	139,985		^(c)
Discontinued operations	—		340,851		^(d)	332,503		^(d)
Total assets	$	3,853,628	$	4,127,083		$	3,945,569

____________


(a)	Upon commercial operation on Dec. 31, 2011 of the new generating facility constructed by Colorado IPP at our Pueblo Airport Generation site, the PPA under which energy and capacity is sold to Colorado Electric is accounted for as a capital lease. Therefore, commencing Dec. 31, 2011, assets previously recorded at Power Generation are now accounted for at Colorado Electric as a capital lease.


(b)	2012 includes a ceiling test impairment and the sale of the Williston Basin assets by our Oil and Gas segment. See Notes 15 and 16.


(c)	Assets of the Corporate segment were reclassified due to deferred taxes that were not classified as discontinued operations.


(d)	See Note 17 for further information relating to discontinued operations.

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

Commodity Derivatives [Member] | Oil and Gas [Member]

Risk Management Activities Risk Management (Tables)

9 Months Ended

Sep. 30, 2012

Cash flow heding instruments included in financial statements

We had the following derivatives and related balances for our Oil and Gas segment (dollars in thousands) as of:



	Sept. 30, 2012					Dec. 31, 2011					Sept. 30, 2011
	Crude Oil Swaps/ Options		Natural Gas Swaps			Crude Oil Swaps/ Options			Natural Gas Swaps		Crude Oil Swaps/ Options		Natural Gas Swaps
Notional ^(a)	537,000		7,455,250			528,000			5,406,250		414,000		4,957,250
Maximum terms in years ^(b)	1.00		1.00			1.25			1.75		1.00		0.25
Derivative assets, current	$	1,651	$	2,032		$	729		$	8,010	$	1,885	$	6,937
Derivative assets, non-current	$	494	$	39		$	771		$	1,148	$	2,529	$	717
Derivative liabilities, current	$	527	$	1,040		$	2,559		$	—	$	—	$	—
Derivative liabilities, non-current	$	414	$	141		$	811		$	7	$	—	$	7
Pre-tax accumulated other comprehensive income (loss)	$	428	$	(344	)	$	(1,928	)	$	9,152	$	4,257	$	7,647
Cash collateral included in Derivative liabilities	$	—	$	—		$	—		$	—	$	—	$	—
Cash collateral included in Other current assets	$	1,126	$	1,288		$	—		$	—	$	—	$	—
Expense included in Revenue ^(c)	$	350	$	54		$	58		$	—	$	157	$	—

____________


(a)	Crude oil in Bbls, gas in MMBtus.


(b)	Refers to the term of the derivative instrument. Assets and liabilities are classified as current or non-current based on the term of the hedged transaction and the corresponding settlement of the derivative instruments.


(c)	Represents the amortization of put premiums.

Commodity Derivatives [Member] | Utilities Group [Member]

Cash flow heding instruments included in financial statements

We had the following derivative balances related to the hedges in our Utilities (in thousands) as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
Derivative assets, current	$	12,380	$	9,844	$	3,355
Derivative assets, non-current	$	634	$	52	$	—
Derivative liabilities, non-current	$	4,527	$	7,156	$	1,360
Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	9,318	$	17,556	$	11,813
Included in Derivatives:
Cash collateral receivable (payable)	$	15,740	$	19,416	$	12,058
Option premiums and commissions	$	2,065	$	880	$	1,750

Contract or notional amounts and terms of marketing activities and derivative commodity instruments

The contract notional amounts and terms of the natural gas derivative commodity instruments held at our Utilities were as follows as of:



	Sept. 30, 2012		Dec. 31, 2011		Sept. 30, 2011
	Notional (MMBtus)	Maximum Term (months)	Notional (MMBtus)	Maximum Term (months)	Notional (MMBtus)	Maximum Term (months)
Natural gas futures purchased	14,690,000	75	14,310,000	84	9,890,000	18
Natural gas options purchased	5,560,000	6	1,720,000	3	3,880,000	6
Natural gas basis swaps purchased	8,800,000	75	7,160,000	60	—	—

Interest Rate Swap [Member]

Interest rate swaps and related balances

Our interest rate swaps and related balances were as follows (dollars in thousands) as of:



	Sept. 30, 2012						Dec. 31, 2011						Sept. 30, 2011
	Designated Interest Rate Swaps			De-designated Interest Rate Swaps*			Designated Interest Rate Swaps			De-designated Interest Rate Swaps*			Designated Interest Rate Swaps			De-designated Interest Rate Swaps*
Notional	$	150,000		$	250,000		$	150,000		$	250,000		$	150,000		$	250,000
Weighted average fixed interest rate	5.04		%	5.67		%	5.04		%	5.67		%	5.04		%	5.67		%
Maximum terms in years	4.25			1.25			5.00			2.00			5.25			0.25
Derivative liabilities, current	$	7,028		$	77,914		$	6,513		$	75,295		$	6,724		$	94,588
Derivative liabilities, non-current	$	18,660		$	17,668		$	20,363		$	20,696		$	21,108		$	—
Pre-tax accumulated other comprehensive income (loss)	$	(25,688	)	$	—		$	(26,876	)	$	—		$	(27,832	)	$	—
Year-to Date pre-tax gain (loss)	$	—		$	(2,902	)	$	—		$	(42,010	)	$	—		$	(40,608	)
Cash collateral receivable (payable) included in derivative	$	—		$	3,310		$	—		$	—		$	—		$	—

_____________


*	Maximum terms in years reflect the amended early termination dates. If the early termination dates are not extended, the swaps will require cash settlement based on the swap value on the termination date. If extended, de-designated swaps totaling $100 million notional terminate in 6.25 years and de-designated swaps totaling $150 million notional terminate in 16.25 years.

Fair Value Measurements Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2012

Derivative Instruments, Gain (Loss)

Fair value assets and liabilities measured on recurring basis

The following tables set forth by level within the fair value hierarchy our assets and liabilities that were accounted for at fair value on a recurring basis (in thousands):



	As of Sept. 30, 2012
	Level 1		Level 2			Level 3			Counterparty Netting		Cash Collateral			Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	619		$	—		$	—	$	—		$	619
Basis Swaps -- Oil	—		1,526			—			—		—			1,526
Options -- Gas	—		—			—			—		—			—
Basis Swaps -- Gas	—		2,071			—			—		—			2,071
Commodity derivatives — Utilities	—		(2,760		)	34		^(b)	—		15,740			13,014
Cash and cash equivalents ^(a)	247,192		—			—			—		—			247,192
Total	$	247,192	$	1,456		$	34		$	—	$	15,740		$	264,422

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	885		$	—		$	—	$	—		$	885
Basis Swaps -- Oil	—		56			—			—		—			56
Options -- Gas	—		—			—			—		—			—
Basis Swaps -- Gas	—		1,181			—			—		—			1,181
Commodity derivatives — Utilities	—		4,527			—			—		—			4,527
Interest rate swaps	—		124,580			—			—		(3,310		)	121,270
Total	$	—	$	131,229		$	—		$	—	$	(3,310	)	$	127,919

______________


(a)	Level 1 assets and liabilities are described in Note 13.

(b)



	As of Dec. 31, 2011
	Level 1		Level 2			Level 3			Counterparty Netting		Cash Collateral		Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	768	^(a)	$	5	$	—	$	773
Basis Swaps -- Oil	—		727			—			—		—		727
Options -- Gas	—		—			—			—		—		—
Basis Swaps -- Gas	—		9,158			—			—		—		9,158
Commodity derivatives —Utilities	—		(9,520		)	—			—		19,416		9,896
Money market funds	6,005		—			—			—		—		6,005
Total	$	6,005	$	365		$	768	^(a)	$	5	$	19,416	$	26,559

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	1,165	^(a)	$	5	$	—	$	1,170
Basis Swaps -- Oil	—		2,200			—			—		—		2,200
Options -- Gas	—		—			—			—		—		—
Basis Swaps -- Gas	—		7			—			—		—		7
Commodity derivatives — Utilities	—		7,156			—			—		—		7,156
Interest rate swaps	—		122,867			—			—		—		122,867
Total	$	—	$	132,230		$	1,165	^(a)	$	5	$	—	$	133,400

_________


(a)	Of the net balance included as Level 3, transfers out of Level 3 included settlement of losses of approximately $0.5 million within AOCI and approximately $0.9 million transferred to level 2 as inputs becoming more observable.



	As of Sept. 30, 2011
	Level 1		Level 2			Level 3		Counterparty Netting		Cash Collateral		Total
Assets:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	328	$	—	$	—	$	328
Basis Swaps -- Oil	—		4,086			—		—		—		4,086
Options -- Gas	—		—			—		—		—		—
Basis Swaps -- Gas	—		7,654			—		—		—		7,654
Commodity derivatives — Utilities	—		(8,703		)	—		—		12,058		3,355
Money market funds	9,006		—			—		—		—		9,006
Total	$	9,006	$	3,037		$	328	$	—	$	12,058	$	24,429

Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—	$	—		$	—	$	—	$	—	$	—
Basis Swaps -- Oil	—		—			—		—		—		—
Options -- Gas	—		—			—		—		—		—
Basis Swaps -- Gas	—		7			—		—		—		7
Commodity derivatives — Utilities	—		1,360			—		—		—		1,360
Interest rate swaps	—		122,420			—		—		—		122,420
Total	$	—	$	123,787		$	—	$	—	$	—	$	123,787

Fair value and balance sheet classification of derivative instruments

The following tables present the fair value and balance sheet classification of our derivative instruments (in thousands):



As of Sept. 30, 2012
	Balance Sheet Location	Fair Value of Asset Derivatives		Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	3,263	$	—
Commodity derivatives	Derivative assets — non-current	533		—
Commodity derivatives	Derivative liabilities — current	—		1,534
Commodity derivatives	Derivative liabilities — non-current	—		555
Interest rate swaps	Derivative liabilities — current	—		7,029
Interest rate swaps	Derivative liabilities — non-current	—		18,661
Total derivatives designated as hedges		$	3,796	$	27,779

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	421	$	3,361
Commodity derivatives	Derivative assets — non-current	—		(634		)
Commodity derivatives	Derivative liabilities — current	—		33
Commodity derivatives	Derivative liabilities — non-current	—		4,527
Interest rate swaps	Derivative liabilities — current	—		77,913
Interest rate swaps	Derivative liabilities — non-current	—		20,977
Total derivatives not designated as hedges		$	421	$	106,177



As of Dec. 31, 2011
	Balance Sheet Location	Fair Value of Asset Derivatives		Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	8,739	$	—
Commodity derivatives	Derivative assets — non-current	1,919		—
Commodity derivatives	Derivative liabilities — current	—		2,559
Commodity derivatives	Derivative liabilities — non-current	—		818
Interest rate swaps	Derivative liabilities — current	—		6,513
Interest rate swaps	Derivative liabilities — non-current	—		20,363
Total derivatives designated as hedges		$	10,658	$	30,253

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	—	$	9,572
Commodity derivatives	Derivative assets — non-current	—		(52		)
Commodity derivatives	Derivative liabilities — current	—		—
Commodity derivatives	Derivative liabilities — non-current	—		7,156
Interest rate swaps	Derivative liabilities — current	—		75,295
Interest rate swaps	Derivative liabilities — non-current	—		20,696
Total derivatives not designated as hedges		$	—	$	112,667



As of Sept. 30, 2011
	Balance Sheet Location	Fair Value of Asset Derivatives			Fair Value of Liability Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current	$	8,822		$	—
Commodity derivatives	Derivative assets — non-current	3,246			—
Commodity derivatives	Derivative liabilities — current	—			—
Commodity derivatives	Derivative liabilities — non-current	—			7
Interest rate swaps	Derivative liabilities — current	—			6,724
Interest rate swaps	Derivative liabilities — non-current	—			21,108
Total derivatives designated as hedges		$	12,068		$	27,839

Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current	$	—		$	8,703
Commodity derivatives	Derivative assets — non-current	—			—
Commodity derivatives	Derivative liabilities — current	(2		)	(1,360		)
Commodity derivatives	Derivative liabilities — non-current	—			—
Interest rate swaps	Derivative liabilities — current	—			94,588
Interest rate swaps	Derivative liabilities — non-current	—			—
Total derivatives not designated as hedges		$	(2	)	$	101,931

Cash Flow Hedging [Member]

Derivative Instruments, Gain (Loss)

Cash flow hedges included in Accumulated Other Comprehensive Income

The impact of cash flow hedges on our Condensed Consolidated Statements of Income was as follows (in thousands):



Three Months Ended Sept. 30, 2012
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(1,684	)	Interest expense	$	(1,853	)		$	—
Commodity derivatives	(3,111		)	Revenue	1,838				—
Total	$	(4,795	)		$	(15	)		$	—



Three Months Ended Sept. 30, 2011
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(6,958	)	Interest expense	$	(1,930	)		$	—
Commodity derivatives	10,095			Revenue	1,516				—
Total	$	3,137			$	(414	)		$	—



Nine Months Ended Sept. 30, 2012
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(4,697	)	Interest expense	$	(5,518	)		$	—
Commodity derivatives	601			Revenue	7,741				—
Total	$	(4,096	)		$	2,223			$	—



Nine Months Ended Sept. 30, 2011
Derivatives in Cash Flow Hedging Relationships	Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)			Location of Gain/(Loss) Reclassified from AOCI into Income (Effective Portion)	Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)			Location of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)
Interest rate swaps	$	(11,428	)	Interest expense	$	(5,741	)		$	—
Commodity derivatives	9,784			Revenue	2,849				—
Total	$	(1,644	)		$	(2,892	)		$	—

Not Designated as Hedging Instrument [Member]

Derivative Instruments, Gain (Loss)

Gains and losses recognized in income

The impact of derivative instruments that have not been designated as hedging instruments on our Condensed Consolidated Statements of Income was as follows (in thousands):



		Three Months Ended			Nine Months Ended
		Sept. 30, 2012			Sept. 30, 2012
Derivatives Not Designated as Hedging Instruments	Location of Gain/(Loss) on Derivatives Recognized in Income	Amount of Gain/(Loss) on Derivatives Recognized in Income			Amount of Gain/(Loss) on Derivatives Recognized in Income
Interest rate swaps - unrealized	Unrealized gain (loss) on interest rate swaps, net	$	605		$	(2,902	)
Interest rate swaps - realized	Interest expense	(3,250		)	(9,697		)
Commodity derivatives	Revenue	(14		)	(14		)
		$	(2,659	)	$	(12,613	)



		Three Months Ended			Nine Months Ended
		Sept. 30, 2011			Sept. 30, 2011
Derivatives Not Designated as Hedging Instruments	Location of Gain/(Loss) on Derivatives Recognized in Income	Amount of Gain/(Loss) on Derivatives Recognized in Income			Amount of Gain/(Loss) on Derivatives Recognized in Income
Interest rate swaps - unrealized	Unrealized gain (loss) on interest rate swaps, net	$	(38,246	)	$	(40,608	)
Interest rate swaps - realized	Interest expense	(3,373		)	(10,077		)
		$	(41,619	)	$	(50,685	)

Tabular disclosure of the location and amount of gains and losses reported in the statement of financial performance, or when applicable, the statement of financial position. For example, (a) gains and losses recognized in the income statement on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges and (b) gains and losses initially recognized in other comprehensive income on derivative instruments designated and qualifying as cash flow hedges.

Fair Value of Financial Instruments [Abstract]

Fair Value of Financial Instruments Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2012

Fair value of financial instruments

The estimated fair values of our financial instruments are as follows (in thousands) as of:



	Sept. 30, 2012				Dec. 31, 2011				Sept. 30, 2011
	Carrying Amount		Fair Value		Carrying Amount		Fair Value		Carrying Amount		Fair Value
Cash and cash equivalents ^(a)	$	247,192	$	247,192	$	21,628	$	21,628	$	30,198	$	30,198
Restricted cash and equivalents ^(a)	$	7,302	$	7,302	$	9,254	$	9,254	$	4,080	$	4,080
Notes receivable ^(a)	$	21,832	$	21,832	$	—	$	—	$	—	$	—
Notes payable ^(b)	$	225,000	$	225,000	$	345,000	$	345,000	$	359,000	$	359,000
Long-term debt, including current maturities ^(c)	$	1,271,260	$	1,471,932	$	1,282,882	$	1,464,289	$	1,285,087	$	1,430,271

____________


(a)	Fair value approximates carrying value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates and therefore is classified in Level 1 in the fair value hierarchy.


(b)	The carrying amounts of our notes payable approximate fair value due to their variable interest rates with short reset periods.


(c)	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13476-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13467-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6447952&loc=d3e13220-108610

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 19
-Subparagraph a, b, c(1), d(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 14
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15
-Subparagraph b-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph c(2), d, e, f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph a, c(1), c(2), c(3), d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Cash proceeds from sale of operating assets [Table Text Block]

Sale of Assets Sale of Assets (Tables)

9 Months Ended

Sep. 30, 2012

Sale of Operating Assets [Abstract]

Net cash proceeds were as follows (in thousands):



Cash proceeds received on date of sale	$	243,314

Adjustments to proceeds:
Post close adjustments	1,490
Transaction adviser fees	(1,400		)
Estimated payment for contractual obligation related to "back-in" fee *	(16,847		)

Net cash proceeds	$	226,557

_____________

* Required payment, triggered by the sale of the property, arising from a contractual obligation contained in the original participation agreement with the property operator.

Discontinued Operations Discontinued Operations (Tables)

9 Months Ended

Sep. 30, 2012

Condensed Statement of Income [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]



	For the Three Months Ended						For the Nine Months Ended
	Sept. 30, 2012			Sept. 30, 2011			Sept. 30, 2012			Sept. 30, 2011

Revenue	$	—		$	6,937		$	(604	)	$	21,878

Pre-tax income (loss) from discontinued operations	$	(311	)	$	1,495		$	(6,622	)	$	4,404
Pre-tax gain (loss) on sale	—			—			(3,787		)	—
Income tax (expense) benefit	145			(857		)	3,599			(1,878		)

Income (loss) from discontinued operations, net of tax ^(a)	$	(166	)	$	638		$	(6,810	)	$	2,526

_____________


(a)	Includes transaction related costs, net of tax, of $0.2 million and $2.5 million for three and nine months ended Sept. 30, 2012, respectively.

Condensed Balance Sheet [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Net assets of the Energy Marketing segment included in Assets/Liabilities of discontinued operations in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands) as of:



	Dec. 31, 2011			Sept. 30, 2011

Other current assets	$	280,221		$	282,361
Derivative assets, current and non-current	52,859			50,519
Property, plant and equipment, net	5,828			5,391
Goodwill	1,435			1,435
Other non-current assets	508			(7,204		)
Other current liabilities	(132,951		)	(134,747		)
Derivative liabilities, current and non-current	(26,084		)	(31,978		)
Other non-current liabilities	(14,894		)	(4,959		)
Net assets	$	166,922		$	160,818

Tabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.

Supplemental Disclosure of Cash Flow Information Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Non-cash investing activities from continuing operations -
Property, plant and equipment acquired with accrued liabilities	$ 39,303	$ 49,566
Capitalized asset associated with retirement obligations	3,806	0
Cash (paid) refunded during the period for continuing operations -
Interest (net of amounts capitalized)	(69,901)	(60,934)
Income taxes, net	$ 425	$ 11,939

Materials, Supplies and Fuel Materials, Supplies and Fuel (Details) - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Materials and supplies	$ 43,847	$ 40,838	$ 37,327
Natural gas in storage held for distribution	28,764	35,025	38,641
Total materials, supplies and fuel	80,900	84,064	84,607
Electric Utilities [Member]
Fuel - Electric Utilities	$ 8,289	$ 8,201	$ 8,639

Accounts Receivable Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ (912)	$ (1,661)	$ (1,540)
Accounts receivable, net	104,482	156,774	102,673
Electric Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	(603)	(545)	(590)
Accounts receivable, net	64,640	63,379	57,700
Gas Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	(204)	(1,011)	(789)
Accounts receivable, net	27,474	77,334	32,897
Oil and Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	(105)	(105)	(161)
Accounts receivable, net	10,167	11,177	8,659
Coal Mining [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	0	0	0
Accounts receivable, net	1,540	4,056	1,845
Power Generation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	0	0	0
Accounts receivable, net	4	282	119
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable, Current	0	0	0
Accounts receivable, net	657	546	1,453
Billed Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	77,473	98,292	75,294
Billed Revenues [Member] \| Electric Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	46,802	42,773	41,889
Billed Revenues [Member] \| Gas Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	18,198	39,353	21,168
Billed Revenues [Member] \| Oil and Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	10,272	11,282	8,820
Billed Revenues [Member] \| Coal Mining [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	1,540	4,056	1,845
Billed Revenues [Member] \| Power Generation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	4	282	119
Billed Revenues [Member] \| Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	657	546	1,453
Unbilled Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	27,921	60,143	28,919
Unbilled Revenues [Member] \| Electric Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	18,441	21,151	16,401
Unbilled Revenues [Member] \| Gas Utilities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	9,480	38,992	12,518
Unbilled Revenues [Member] \| Oil and Gas [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	0	0	0
Unbilled Revenues [Member] \| Coal Mining [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	0	0	0
Unbilled Revenues [Member] \| Power Generation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	0	0	0
Unbilled Revenues [Member] \| Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross, Current	$ 0	$ 0	$ 0

Notes Payable Notes Payable (Details) - USD ($)
$ in Thousands

9 Months Ended

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2011

Letters of Credit, Amount Outstanding

$ 225,000

$ 345,000

$ 359,000

36,300

43,700

42,355

Consolidated Net Worth, Actual

1,214,317

1,209,336

1,088,005

Line of Credit, Covenant Requirement, Consolidated Net Worth, Minimum

$ 909,511

Recourse Leverage Ratio

56.30%

Line of Credit, Covenant Requirement, Recourse Leverage Ratio

65.00%

Line of Credit [Member]

Letters of Credit, Amount Outstanding

$ 75,000

195,000

209,000

36,300

43,700

42,355

Line of Credit Facility, Current Borrowing Capacity

$ 500,000

Line of Credit Facility, Expiration Date

Feb. 01, 2017

Line of Credit Facility, Maximum Borrowing Capacity

$ 750,000

Line of Credit Facility, Commitment Fee Percentage

0.25%

Deferred Financing Costs Remaining on Balance Sheet

$ 2,800

Write off of Deferred Debt Issuance Cost

$ 1,500

Line of Credit [Member] | Base Rate Option [Member]

Line of Credit Facility, Interest Rate at Period End

0.50%

Line of Credit [Member] | Eurodollar Option [Member]

Line of Credit Facility, Interest Rate at Period End

1.50%

Line of Credit [Member] | Letter of Credit [Member]

Line of Credit Facility, Interest Rate at Period End

1.50%

Corporate Term Loan due June 2012 [Member] | Loans Payable [Member]

Letters of Credit, Amount Outstanding

$ 150,000

^[1]

150,000

$ 0

Debt Instrument, Maturity Date

Jun. 24, 2013

Debt Instrument, Basis Spread on Variable Rate

1.10%

[1]	In June 2012, this short-term loan was extended for one year. See discussion below.

Long-Term Debt Long-Term Debt (Details) - Electric Utilities [Member] - Polution Control Revenue Bonds Due 2014 [Member] $ in Millions	May 15, 2012 USD ($)
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	4.80%
Early Repayment of Subordinated Debt	$ 6.5
Debt Instrument, Maturity Date	Oct. 01, 2014

Earnings per Share Reconcilation of Basic to Dilutive Shares (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (loss) from continuing operations	$ 34,623	$ (11,163)	$ 57,571	$ 21,611
Weighted average shares - basic	43,847	39,145	43,792	39,105
Dilutive effect of:
Dilutive Effect of Restricted Stock and Restricted Stock Units (in shares)	175	0	159	147
Dilutive Effect of Stock Options (in shares)	12	0	14	16
Dilutive Effect of Equity forward issuance (in shares)	0	0	0	473
Dilutive Effect of Other Stock (in shares)	74	0	61	51
Weighted average shares - diluted	44,108	39,145	44,026	39,792

Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.13)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
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-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4613673-111683

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph b(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1448-109256

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Weighted-Average Number of Common Shares Outstanding
-URI http://asc.fasb.org/extlink&oid=6528421

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Earnings per Share Anti-dilutive shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Shares Excluded from Computation of Earnings Per Share	138,000	223,000	173,000	155,000
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Shares Excluded From Diluted Earnings Per Share Due To Net Loss		11,880
Restricted Stock and Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Shares Excluded From Diluted Earnings Per Share Due To Net Loss		159,873
Other Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Shares Excluded From Diluted Earnings Per Share Due To Net Loss		31,408
Equity Forward Agreements [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Shares Excluded From Diluted Earnings Per Share Due To Net Loss		424,715
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Shares Excluded from Computation of Earnings Per Share	77,000	176,000	101,000	119,000
Restricted Stock and Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Shares Excluded from Computation of Earnings Per Share	61,000	20,000	53,000	17,000
Other Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Shares Excluded from Computation of Earnings Per Share	0	27,000	19,000	19,000

Employee Benefit Plans Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,431	$ 1,355	$ 4,291	$ 4,066
Interest cost	3,688	3,732	11,062	11,196
Expected return on plan assets	(4,084)	(4,239)	(12,252)	(12,717)
Prior service cost	22	25	66	75
Net loss (gain)	2,408	1,135	7,224	3,405
Net periodic benefit cost	3,465	2,008	10,391	6,025
Contributions Made	0		25,000
Contributions Remaining in Current Fiscal Year	0		0
Contributions Anticipated in Next Fiscal Year	4,500		4,500
Non-pension Postretirement Healthcare Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	402	375	1,206	1,125
Interest cost	523	542	1,569	1,626
Expected return on plan assets	(19)	(41)	(57)	(123)
Prior service cost	(125)	(120)	(375)	(360)
Net loss (gain)	222	169	666	507
Net periodic benefit cost	1,003	925	3,009	2,775
Contributions Made	1,063		3,189
Contributions Remaining in Current Fiscal Year	1,063		1,063
Contributions Anticipated in Next Fiscal Year	4,380		4,380
Supplemental Non-qualified Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	243	257	735	771
Interest cost	331	324	993	973
Prior service cost	1	1	3	3
Net loss (gain)	202	128	606	383
Net periodic benefit cost	777	$ 710	2,337	$ 2,130
Contributions Made	278		834
Contributions Remaining in Current Fiscal Year	278		278
Contributions Anticipated in Next Fiscal Year	$ 1,090		$ 1,090

Segment Reporting Income Statement (Details) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Feb. 29, 2012

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2012

Sep. 30, 2011

$ 246,808

$ 253,072

$ 855,022

$ 916,023

(3,549)

(5,016)

Income (loss) from continuing operations

34,457

(10,525)

50,761

24,137

34,623

(11,163)

57,571

21,611

Gain (Loss) On Sale Of Oil And Gas Properties, After-Tax

(17,700)

Increase Decrease in Fair Value of Derivative Instruments Not Designated as Hedging Instruments Net of Tax Included in Net Income

(400)

24,900

1,900

26,400

Overhead Of Discontinued Operations, Net of Tax

500

1,600

1,500

Impairment of Oil and Gas Properties After Tax

17,300

Electric Utilities [Member]

151,281

151,063

451,974

431,624

3,736

2,653

11,946

9,902

14,573

15,790

37,478

34,653

Gas Utilities [Member]

63,435

72,651

314,343

402,839

572

16,369

24,275

Oil and Gas [Member]

24,728

19,163

66,994

55,907

Power Generation [Member]

17,389

^[1]

241

(2,219)

^[1],[2]

(553)

1,256

1,011

3,193

2,589

19,695

7,089

56,119

20,911

5,128

337

15,968

2,071

Coal Mining [Member]

6,108

9,184

18,518

23,064

8,567

8,651

24,273

25,806

Energy Marketing [Member]

1,690

555

3,924

(1,124)

Significant Acquisitions and Disposals, Date of Transaction for Acquisition or Disposal

Feb. 29, 2012

Unallocated Amount to Segment [Member]

^[3]

(4,160)

(28,307)

^[4]

(13,949)

^[4]

(37,299)

^[4]

Corporate [Member]

(31,998)

(21,942)

(92,338)

(61,635)

$ 0

$ (351)

$ 0

$ (412)

[1]	Income (loss) from continuing operations includes a $17.7 million after-tax gain on the sale of the Williston Basin assets. See Note 15.
[2]	Income (loss) from continuing operations includes a $17.3 million non-cash after-tax ceiling test impairment expense. See Note 16 for further information.
[3]	Income (loss) from continuing operations includes $0.4 million net after-tax non-cash mark-to-market gain and $1.9 million net after-tax non-cash mark-to-market loss on interest rate swaps for the three and nine months ended Sept. 30, 2012, respectively, and a $24.9 million and $26.4 million net after-tax non-cash mark-to-market loss on interest rate swaps for the three and nine months ended Sept. 30, 2011, respectively.
[4]	Certain indirect corporate costs and inter-segment interest expenses after-tax totaling $0.5 million for the three months ended Sept. 30, 2011 and $1.6 million and $1.5 million for the nine months ended Sept. 30, 2012 and 2011 were included in the Corporate segment in continuing operations and were not reclassified as discontinued operations. See Note 17 for further information.

Segment Reporting Assets (Details) - USD ($)
$ in Thousands

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2011

Electric Utilities [Member]

$ 3,853,628

$ 4,127,083

$ 3,945,569

2,302,951

^[1]

2,254,914

^[1]

1,917,184

Gas Utilities [Member]

710,099

746,444

683,163

Oil and Gas [Member]

Power Generation [Member]

263,088

^[2]

425,970

405,513

119,489

^[1]

129,121

^[1]

372,313

Coal Mining [Member]

Unallocated Amount to Segment [Member]

90,444

88,704

94,908

Segment, Discontinued Operations [Member]

367,557

141,079

^[3]

139,985

^[3]

$ 0

$ 340,851

^[4]

$ 332,503

^[4]

[1]	Upon commercial operation on Dec. 31, 2011 of the new generating facility constructed by Colorado IPP at our Pueblo Airport Generation site, the PPA under which energy and capacity is sold to Colorado Electric is accounted for as a capital lease. Therefore, commencing Dec. 31, 2011, assets previously recorded at Power Generation are now accounted for at Colorado Electric as a capital lease.
[2]	2012 includes a ceiling test impairment and the sale of the Williston Basin assets by our Oil and Gas segment. See Notes 15 and 16.
[3]	Assets of the Corporate segment were reclassified due to deferred taxes that were not classified as discontinued operations.
[4]	See Note 17 for further information relating to discontinued operations.

Risk Management Activities Risk Management (Details)
$ in Thousands

3 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2012

USD ($)

Btu

bbl

Sep. 30, 2011

USD ($)

Btu

bbl

Sep. 30, 2012

USD ($)

Btu

bbl

Sep. 30, 2011

USD ($)

Btu

bbl

Dec. 31, 2011

USD ($)

Btu

bbl

$ 16,063

$ 12,177

$ 16,063

$ 12,177

$ 18,583

1,167

3,246

1,167

3,246

1,971

86,509

101,312

86,509

101,312

84,367

Unrealized Gain (Loss) on Derivatives

41,410

22,475

41,410

22,475

49,033

3,522

2,305

Oil and Gas [Member]

Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months

1,200

Oil and Gas [Member] | Natural Gas [Member]

Derivative, Collateral, Right to Reclaim Cash

1,288

Oil and Gas [Member] | Crude Oil [Member]

Derivative, Collateral, Right to Reclaim Cash

1,126

Utilities Group [Member]

12,380

3,355

12,380

3,355

9,844

634

4,527

1,360

4,527

1,360

7,156

Net Unrealized Gain (Loss) Included in Regulatory Assets

15,740

12,058

15,740

12,058

19,416

9,318

11,813

9,318

11,813

17,556

Option Premium Included in Derivative Assets, Current

2,065

1,750

2,065

1,750

880

Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]

77,914

94,588

77,914

94,588

75,295

17,668

20,696

Latest Expiration, Maximum terms (months)

3,310

$ 3,310

$ 0

1 year 3 months

3 months

2 years

Derivative, Average Interest Rate

$ 250,000

5.67%

Gain (Loss) on Derivative Instruments, Net, Pretax

$ (2,902)

$ (40,608)

$ (42,010)

Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Dedesignated Interest Rate Swap Expiring 2018 [Member]

^[1]

6 years 3 months

Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Dedesignated Interest Rate Swaps Expiring 2028 [Member]

100,000

$ 100,000

^[1]

16 years 3 months

Not Designated as Hedging Instrument [Member] | Credit Risk [Member] | Interest Rate Swap [Member]

150,000

$ 150,000

Potential Future Exposure on Credit Related Contingent Feature

50,000

20,000

$ 20,000

Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]

Maximum Length of Time Hedged in Cash Flow Hedge (years)

4 years 3 months

5 years 3 months

5 years

7,028

6,724

$ 7,028

$ 6,724

$ 6,513

18,660

21,108

18,660

21,108

20,363

(25,688)

(27,832)

(25,688)

(27,832)

(26,876)

Derivative, Average Interest Rate

$ 150,000

5.04%

Gain (Loss) on Derivative Instruments, Net, Pretax

$ 0

Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]

Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net

$ (7,000)

Swaps and Options [Member] | Oil and Gas [Member] | Crude Oil [Member]

Derivative, Nonmonetary Notional Amount | bbl

^[2]

537,000

414,000

537,000

414,000

528,000

Maximum Length of Time Hedged in Cash Flow Hedge (years)

^[3]

1 year

1 year 3 months

$ 1,651

$ 1,885

$ 1,651

$ 1,885

$ 729

494

2,529

494

2,529

771

527

2,559

414

811

Expense included in Revenue

$ 428

$ 4,257

428

4,257

(1,928)

^[4]

$ 350

$ 157

$ 58

Swap [Member] | Oil and Gas [Member] | Natural Gas [Member]

Maximum Length of Time Hedged in Cash Flow Hedge (years)

^[2]

7,455,250

4,957,250

7,455,250

4,957,250

5,406,250

^[3]

1 year

3 months

1 year 9 months

$ 2,032

$ 6,937

$ 2,032

$ 6,937

$ 8,010

717

1,148

1,040

141

Expense included in Revenue

$ (344)

$ 7,647

(344)

7,647

9,152

^[4]

$ 54

$ 0

Future [Member] | Utilities Group [Member] | Natural Gas [Member] | Purchase Contract [Member]

14,690,000

9,890,000

14,690,000

9,890,000

14,310,000

Commodity Option [Member] | Utilities Group [Member] | Natural Gas [Member] | Purchase Contract [Member]

75 months

18 months

84 months

5,560,000

3,880,000

5,560,000

3,880,000

1,720,000

Basis Swap [Member] | Utilities Group [Member] | Natural Gas [Member] | Purchase Contract [Member]

6 months

3 months

8,800,000

7,160,000

Fair Value, Assets, Level 1 to Level 2 Transfers, Amount

75 months

0 years

60 months

[1]	Maximum terms in years reflect the amended early termination dates. If the early termination dates are not extended, the swaps will require cash settlement based on the swap value on the termination date. If extended, de-designated swaps totaling $100 million notional terminate in 6.25 years and de-designated swaps totaling $150 million notional terminate in 16.25 years.
[2]	Crude oil in Bbls, gas in MMBtus.
[3]	Refers to the term of the derivative instrument. Assets and liabilities are classified as current or non-current based on the term of the hedged transaction and the corresponding settlement of the derivative instruments.
[4]	Represents the amortization of put premiums.

Fair Value Measurements Fair Value Heirarchy Assets and Liabilities (Details) - USD ($)
$ in Thousands

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2011

Recurring Fair Value Measures

$ 0

Fair Value, Assets, Level 2 to Level 1 Transfers, Amount

Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount

Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount

Fair Value, Measurements, Recurring [Member] | Level 1 [Member]

247,192

6,005

9,006

Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest Rate Swap [Member]

247,192

^[1]

6,005

9,006

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Level 2 [Member]

1,456

365

3,037

Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

131,229

132,230

123,787

(2,760)

(9,520)

(8,703)

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

4,527

7,156

1,360

Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

124,580

122,867

122,420

Fair Value, Measurements, Recurring [Member] | Level 3 [Member]

768

^[2]

328

Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

1,165

^[2]

^[3]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest Rate Swap [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Counterparty Netting [Member]

Fair Value, Measurements, Recurring [Member] | Counterparty Netting [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Counterparty Netting [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Counterparty Netting [Member] | Interest Rate Swap [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Cash Collateral [Member]

15,740

19,416

12,058

Fair Value, Measurements, Recurring [Member] | Cash Collateral [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

(3,310)

15,740

19,416

12,058

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Fair Value, Measurements, Recurring [Member] | Cash Collateral [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Cash Collateral [Member] | Interest Rate Swap [Member]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

(3,310)

Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]

6,005

9,006

264,422

26,559

24,429

Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Commodity Derivatives [Member] | Utilities Group [Member]

127,919

133,400

123,787

13,014

9,896

3,355

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

4,527

7,156

1,360

Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Cash and Cash Equivalents [Member]

Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value, Fair Value Disclosure [Member] | Interest Rate Swap [Member]

247,192

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

121,270

122,867

122,420

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

619

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

885

768

^[2]

328

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

1,165

^[2]

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

619

773

328

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

885

1,170

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

1,526

727

4,086

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

2,200

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

1,526

727

4,086

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

2,200

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

2,071

9,158

7,654

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

1,181

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

2,071

9,158

7,654

Derivative Financial Instruments, Liabilities, Fair Value Disclosure

$ 1,181

$ 7

[1]	Level 1 assets and liabilities are described in Note 13.
[2]	Of the net balance included as Level 3, transfers out of Level 3 included settlement of losses of approximately $0.5 million within AOCI and approximately $0.9 million transferred to level 2 as inputs becoming more observable.
[3]	The significant unobservable inputs used in the fair value measurement of the long-term OTC contracts are based on the average of price quotes from an independent third party market participant and the OTC contract broker. The unobservable inputs are long-term natural gas prices. Significant changes to these inputs along with the contract term would impact the derivative asset/liability and regulatory asset/liability, but will not impact the results of operations until the contract is settled under the original terms of the contract. The contracts will be classified as Level 2 once settlement is within 60 months of maturity and quoted market prices from a market exchange are available.

Fair Value Measurements Changes in Level 3 Recurring Fair Value (Details) - Oil and Gas [Member] - Commodity Derivatives [Member] $ in Millions	9 Months Ended
	Sep. 30, 2012 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair Value, Net Transfers out of Level 3	$ (0.5)
Fair Value, Asset and Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	$ 0.9

Fair Value Measurements Fair Value Measures (Details) - USD ($) $ in Thousands	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Designated as Hedging Instrument [Member]
Derivatives, Fair Value
Derivative Asset, Fair Value, Net	$ 3,796	$ 10,658	$ 12,068
Derivative Liability, Fair Value, Net	27,779	30,253	27,839
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value
Derivative Asset, Fair Value, Net	421	0	(2)
Derivative Liability, Fair Value, Net	106,177	112,667	101,931
Commodity Derivatives [Member] \| Designated as Hedging Instrument [Member] \| Derivative Assets, Current
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	3,263	8,739	8,822
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Derivatives [Member] \| Designated as Hedging Instrument [Member] \| Derivative Assets, Noncurrent
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	533	1,919	3,246
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Derivatives [Member] \| Designated as Hedging Instrument [Member] \| Derivative Liabilities, Current
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	1,534	2,559	0
Commodity Derivatives [Member] \| Designated as Hedging Instrument [Member] \| Derivative Liabilities, Noncurrent
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	555	818	7
Commodity Derivatives [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Assets, Current
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	421	0	0
Derivative Asset, Fair Value, Gross Liability	3,361	9,572	8,703
Commodity Derivatives [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Assets, Noncurrent
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0	0	0
Derivative Asset, Fair Value, Gross Liability	(634)	(52)	0
Commodity Derivatives [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Liabilities, Current
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	(2)
Derivative Liability, Fair Value, Gross Liability	33	0	(1,360)
Commodity Derivatives [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Liabilities, Noncurrent
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	4,527	7,156	0
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Derivative Liabilities, Current
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	7,029	6,513	6,724
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Derivative Liabilities, Noncurrent
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	18,661	20,363	21,108
Interest Rate Swap [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Liabilities, Current
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	77,913	75,295	94,588
Interest Rate Swap [Member] \| Not Designated as Hedging Instrument [Member] \| Derivative Liabilities, Noncurrent
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	$ 20,977	$ 20,696	$ 0

Fair Value Measurements Hedging Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	$ (4,795)	$ 3,137	$ (4,096)	$ (1,644)
Amount of Reclassfied Gain/(Loss) from AOCI into Income (Effective Portion)	(15)	(414)	2,223	(2,892)
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Cash Flow Hedging [Member] \| Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	(1,684)	(6,958)	(4,697)	(11,428)
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Cash Flow Hedging [Member] \| Interest Rate Swap [Member] \| Interest Expense [Member]
Derivative Instruments, Gain (Loss)
Amount of Reclassfied Gain/(Loss) from AOCI into Income (Effective Portion)	(1,853)	(1,930)	(5,518)	(5,741)
Cash Flow Hedging [Member] \| Commodity Derivatives [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	(3,111)	10,095	601	9,784
Cash Flow Hedging [Member] \| Commodity Derivatives [Member] \| Revenue [Member]
Derivative Instruments, Gain (Loss)
Amount of Reclassfied Gain/(Loss) from AOCI into Income (Effective Portion)	1,838	1,516	7,741	2,849
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) on Derivatives Recognized in Income	(2,659)	(41,619)	(12,613)	(50,685)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member] \| Interest Rate Swap - Unrealized (Loss) Gain [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) on Derivatives Recognized in Income	605	(38,246)	(2,902)	(40,608)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member] \| Interest Expense [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) on Derivatives Recognized in Income	(3,250)	$ (3,373)	(9,697)	$ (10,077)
Not Designated as Hedging Instrument [Member] \| Commodity [Member] \| Interest Rate Swap - Unrealized (Loss) Gain [Member]
Derivative Instruments, Gain (Loss)
Amount of Gain/(Loss) on Derivatives Recognized in Income	$ (14)		$ (14)

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details) - USD ($)
$ in Thousands

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2011

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Cash and cash equivalents

$ 247,192

$ 21,628

$ 30,198

Restricted cash and equivalents

7,302

9,254

4,080

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

225,000

345,000

359,000

Carrying Amount [Member]

Cash and cash equivalents

247,192

21,628

30,198

Restricted cash and equivalents

7,302

9,254

4,080

Notes, Loans and Financing Receivable, Net, Current

21,832

Long-term debt, including current maturities

^[1]

225,000

345,000

359,000

1,271,260

1,282,882

1,285,087

Fair Value [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Cash and cash equivalents, fair value

^[2]

247,192

21,628

30,198

Restricted cash and equivalents, fair value

^[2]

7,302

9,254

4,080

Notes Receivable, Fair Value Disclosure

21,832

^[2]

Notes payable, fair value

^[2]

225,000

345,000

359,000

Long-term debt, including current maturities, fair value

^[3]

$ 1,471,932

$ 1,464,289

$ 1,430,271

[1]	The carrying amounts of our notes payable approximate fair value due to their variable interest rates with short reset periods.
[2]	Fair value approximates carrying value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates and therefore is classified in Level 1 in the fair value hierarchy.
[3]	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

Commitments and Contingencies Dividend Restrictions Subsidiaries (Details) $ in Millions	Sep. 30, 2012 USD ($)
Utilities Group [Member]
Amount of Restricted Net Assets, Subsidiaries	$ 227.2
Non Regulated Energy Group [Member]
Amount of Restricted Net Assets, Subsidiaries	$ 100.0

Sale of Assets Sale of Assets (Details)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 27, 2012

USD ($)

Acres

Gross-Well

Sep. 18, 2012

USD ($)

Sep. 30, 2012

USD ($)

Sep. 30, 2011

USD ($)

Sep. 30, 2012

USD ($)

Sep. 30, 2011

USD ($)

Disposal Date

Sep. 27, 2012

Busch Ranch Wind Farm [Member] | Electric Utilities [Member]

$ 27,285

$ 0

$ 27,285

$ 0

Jointly Owned Utility Plant, Undivided Ownership Percentage

50.00%

Proceeds from Sale of Property, Plant, and Equipment

$ 25,000

Busch Ranch Wind Farm [Member] | Electric Utilities [Member]

Number of MW Sold Under Long-Term Contract | MW

Busch Ranch Wind Farm [Member]

Long-term Contract for Purchase of Electric Power, Date of Contract Expiration

Oct. 16, 2037

Bakken and Three Forks Assets [Member] | Oil and Gas [Member]

Productive Oil and Natural Gas Wells, Number of Wells | Gross-Well

Oil and Natural Gas Acreage, Leased | Acres

28,000

Effective Date, Disposal

Jul. 01, 2012