0001130464-20-000043 | 10-Q | XBRL Viewer

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Document and Entity Information Document - shares	9 Months Ended
Document and Entity Information Document - shares	Sep. 30, 2020	Oct. 31, 2020
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-31303
Entity Registrant Name	Black Hills Corporation
Entity Incorporation, State or Country Code	SD
Entity Tax Identification Number	46-0458824
Entity Address, Address Line One	7001 Mount Rushmore Road
Entity Address, City or Town	Rapid City
Entity Address, State or Province	SD
Entity Address, Postal Zip Code	57702
City Area Code	605
Local Phone Number	721-1700
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common stock of $1.00 par value
Trading Symbol	BKH
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		62,746,692
Entity Central Index Key	0001130464
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31

Condensed Consolidated Statements of Income (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 346,590	$ 325,548	$ 1,210,554	$ 1,257,246
Operating expenses:
Fuel, purchased power and cost of natural gas sold	71,686	73,544	331,194	413,486
Operations and maintenance	122,759	116,583	365,533	365,116
Depreciation, depletion and amortization	56,348	51,884	169,413	154,507
Taxes - property and production	13,563	12,986	42,062	39,454
Total operating expenses	264,356	254,997	908,202	972,563
Operating income	82,234	70,551	302,352	284,683
Other income (expense):
Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts)	(36,521)	(34,000)	(108,067)	(103,677)
Interest income	480	513	1,028	1,208
Impairment of investment	0	(19,741)	(6,859)	(19,741)
Other income (expense), net	(1,193)	580	(703)	55
Total other income (expense)	(37,234)	(52,648)	(114,601)	(122,155)
Income before income taxes	45,000	17,903	187,751	162,528
Income tax (expense)	(4,651)	(2,508)	(25,484)	(22,078)
Net income	40,349	15,395	162,267	140,450
Net income attributable to noncontrolling interest	(4,066)	(3,655)	(11,844)	(10,319)
Net income available for common stock	$ 36,283	$ 11,740	$ 150,423	$ 130,131
Earnings per share of common stock:
Earnings (loss) per share, Basic (usd per share)	$ 0.58	$ 0.19	$ 2.41	$ 2.15
Earnings (loss) per share, Diluted (usd per share)	$ 0.58	$ 0.19	$ 2.41	$ 2.15
Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract]
Basic (in shares)	62,575	60,976	62,310	60,458
Diluted (in shares)	62,630	61,104	62,362	60,578

Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net income	$ 40,349	$ 15,395	$ 162,267	$ 140,450
Other comprehensive income (loss), net of tax:
Benefit plan liability adjustments - net gain (net of tax of $0,$0, $(17) and $0, respectively)	0	0	55	0
Reclassification adjustments of benefit plan liability - prior service cost (net of tax of $6, $3, $19 and $13, respectively)	(18)	(16)	(60)	(45)
Reclassification adjustments of benefit plan liability - net gain (net of tax of $(149), $(92), $(426) and $(197), respectively)	448	(9)	1,365	327
Other comprehensive income, net of tax	1,512	532	3,733	1,221
Comprehensive income	41,861	15,927	166,000	141,671
Less: comprehensive income attributable to noncontrolling interest	4,066	3,655	11,844	10,319
Comprehensive income available for common stock	37,795	12,272	154,156	131,352
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	0	0	(17)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax	6	3	19	13
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	(149)	(92)	(426)	(197)
Interest rate swaps
Other comprehensive income (loss), net of tax:
Reclassification of net realized (gains) losses	544	548	1,630	1,639
Reclassification of net realized gains/losses, (tax) benefit	(168)	(165)	(508)	(500)
Commodity Contracts
Other comprehensive income (loss), net of tax:
Reclassification of net realized (gains) losses	137	124	562	(366)
Net unrealized gains (losses) on commodity derivatives (net of tax of $(112), $35, $(44) and $100, respectively)	401	(115)	181	(334)
Reclassification of net realized gains/losses, (tax) benefit	(41)	(5)	(172)	142
Net unrealized gains/losses on commodity derivatives, (tax) benefit	$ (112)	$ 35	$ (44)	$ 100

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 6,955	$ 9,777
Restricted cash and equivalents	4,257	3,881
Accounts receivable, net	160,478	255,805
Materials, supplies and fuel	126,358	117,172
Derivative assets, current	2,001	342
Income tax receivable, net	20,828	16,446
Regulatory assets, current	49,493	43,282
Other current assets	33,287	26,479
Total current assets	403,657	473,184
Investments	15,659	21,929
Property, plant and equipment	7,128,387	6,784,679
Less: accumulated depreciation and depletion	(1,276,410)	(1,281,493)
Total property, plant and equipment, net	5,851,977	5,503,186
Other assets:
Goodwill	1,299,454	1,299,454
Intangible assets, net	12,242	13,266
Regulatory assets, non-current	221,743	228,062
Other assets, non-current	24,318	19,376
Total other assets, non-current	1,557,757	1,560,158
TOTAL ASSETS	7,829,050	7,558,457
Current liabilities:
Accounts payable	152,010	193,523
Accrued liabilities	244,010	226,767
Derivative liabilities, current	1,439	2,254
Regulatory liabilities, current	22,282	33,507
Notes payable	84,320	349,500
Current maturities of long-term debt	9,871	5,743
Total current liabilities	513,932	811,294
Long-term debt, net of current maturities	3,526,894	3,140,096
Deferred credits and other liabilities:
Deferred income tax liabilities, net	398,136	360,719
Regulatory liabilities, non-current	505,317	503,145
Benefit plan liabilities	144,049	154,472
Other deferred credits and other liabilities	120,522	124,662
Total deferred credits and other liabilities	1,168,024	1,142,998
Commitments and contingencies (See Notes 7, 9, 12, 13)
Equity:
Common stock $1 par value; 100,000,000 shares authorized; issued 62,773,015 and 61,480,658 shares, respectively	62,773	61,481
Additional paid-in capital	1,655,912	1,552,788
Retained earnings	828,993	778,776
Treasury stock, at cost – 24,897 and 3,956 shares, respectively	(1,710)	(267)
Accumulated other comprehensive income (loss)	(26,922)	(30,655)
Total stockholders’ equity	2,519,046	2,362,123
Noncontrolling interest	101,154	101,946
Total equity	2,620,200	2,464,069
TOTAL LIABILITIES AND TOTAL EQUITY	$ 7,829,050	$ 7,558,457
Common Stock, Par Value (usd per share)	$ 1	$ 1
Common Stock Authorized (in shares)	100,000,000	100,000,000
Common Stock Issued (in shares)	62,773,015	61,480,658
Treasury Stock (in shares)	24,897	3,956

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net income	$ 162,267	$ 140,450
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	169,413	154,507
Deferred financing cost amortization	5,523	6,326
Impairment of investment	6,859	19,741
Stock compensation	2,696	8,332
Deferred income taxes	28,502	24,381
Employee benefit plans	9,294	7,965
Other adjustments, net	7,910	9,192
Changes in certain operating assets and liabilities:
Materials, supplies and fuel	(10,905)	(4,126)
Accounts receivable and other current assets	75,960	115,325
Accounts payable and other current liabilities	(11,136)	(83,436)
Regulatory assets - current	1,954	12,455
Regulatory liabilities - current	(17,686)	(15,644)
Payment for Pension Benefits	(12,700)	(12,700)
Other operating activities, net	1,508	3,307
Net cash provided by operating activities	419,459	386,075
Investing activities:
Property, plant and equipment additions	(535,993)	(592,537)
Other investing activities	6,269	(735)
Net cash (used in) investing activities	(529,724)	(593,272)
Financing activities:
Dividends paid on common stock	(99,999)	(91,779)
Common stock issued	99,316	101,361
Net (payments) borrowings of short-term debt	(265,180)	109,280
Long-term debt - issuances	400,000	400,000
Long-term debt - repayments	(7,163)	(304,307)
Distributions to noncontrolling interest	(12,636)	(12,736)
Other financing activities	(6,519)	(1,992)
Net cash provided by financing activities	107,819	199,827
Net change in cash, restricted cash and cash equivalents	(2,446)	(7,370)
Cash, restricted cash and cash equivalents at beginning of period	13,658	24,145
Cash, restricted cash and cash equivalents at end of period	11,212	16,775
Supplemental Cash Flow Information [Abstract]
Interest (net of amounts capitalized)	(87,453)	(99,375)
Income taxes	1,256	2,255
Accrued property, plant and equipment purchases at September 30	$ 86,474	$ 86,661

Condensed Consolidated Statements Of Equity (unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (loss)	Noncontrolling Interest
Common Stock, Shares, Outstanding at Dec. 31, 2018			60,048,567	44,253
Total equity at Dec. 31, 2018	$ 2,287,423		$ 60,049	$ (2,510)	$ 1,450,569	$ 700,396	$ (26,916)	$ 105,835
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	107,362					103,808		3,554
Other comprehensive income (loss), net of tax	457						457
Dividends on Common Stock	(30,332)					(30,332)
Share-based compensation, shares			48,956	(20,497)
Share-based compensation	538		$ 49	$ 1,078	(589)
Issuance of common stock, shares			280,497
Issuance of common stock	19,999		$ 280		19,719
Issuance costs	(289)				(289)
Distributions to noncontrolling interest	(4,846)							(4,846)
Common Stock, Shares, Outstanding at Mar. 31, 2019			60,378,020	23,756
Total equity at Mar. 31, 2019	$ 2,383,702	$ 3,390	$ 60,378	$ (1,432)	1,469,410	777,262	(26,459)	104,543
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.505
Common Stock, Shares, Outstanding at Dec. 31, 2018			60,048,567	44,253
Total equity at Dec. 31, 2018	$ 2,287,423		$ 60,049	$ (2,510)	1,450,569	700,396	(26,916)	105,835
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	140,450
Other comprehensive income (loss), net of tax	1,221
Issuance costs			$ (1,000)
Common Stock, Shares, Outstanding at Sep. 30, 2019			61,480,640	26,572
Total equity at Sep. 30, 2019	2,432,896	3	$ 61,481	$ (1,636)	1,553,190	742,138	(25,695)	103,418
Common Stock, Shares, Outstanding at Mar. 31, 2019			60,378,020	23,756
Total equity at Mar. 31, 2019	2,383,702	3,390	$ 60,378	$ (1,432)	1,469,410	777,262	(26,459)	104,543
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	17,693					14,583		3,110
Other comprehensive income (loss), net of tax	232						232
Dividends on Common Stock	(30,620)					(30,620)
Share-based compensation, shares			54,767	1,603
Share-based compensation	3,890		$ 54	$ (112)	3,948
Issuance of common stock, shares			658,598
Issuance of common stock	50,001		$ 659		49,342
Issuance costs	(492)				(492)
Distributions to noncontrolling interest	(4,405)							(4,405)
Common Stock, Shares, Outstanding at Jun. 30, 2019			61,091,385	25,359
Total equity at Jun. 30, 2019	$ 2,419,998	(3)	$ 61,091	$ (1,544)	1,522,208	761,222	(26,227)	103,248
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.505
Net income (loss)	$ 15,395					11,740		3,655
Other comprehensive income (loss), net of tax	532						532
Dividends on Common Stock	(30,827)					(30,827)
Share-based compensation, shares			18	1,213
Share-based compensation	1,677		$ 0	$ (92)	1,769
Issuance of common stock, shares			389,237
Issuance of common stock	30,001		$ 390		29,611
Issuance costs	(398)		$ (300)		(398)
Distributions to noncontrolling interest	(3,485)							(3,485)
Common Stock, Shares, Outstanding at Sep. 30, 2019			61,480,640	26,572
Total equity at Sep. 30, 2019	$ 2,432,896	3	$ 61,481	$ (1,636)	1,553,190	742,138	(25,695)	103,418
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.505
Common Stock, Shares, Outstanding at Dec. 31, 2019			61,480,658	3,956
Total equity at Dec. 31, 2019	$ 2,464,069		$ 61,481	$ (267)	1,552,788	778,776	(30,655)	101,946
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	97,224					93,174		4,050
Other comprehensive income (loss), net of tax	1,273						1,273
Dividends on Common Stock	(32,902)					(32,902)
Share-based compensation, shares			69,378	20,700
Share-based compensation	674		$ 69	$ (1,658)	2,263
Issuance of common stock, shares			1,222,942
Issuance of common stock	100,000		$ 1,223		98,777
Issuance costs	(967)				(967)
Distributions to noncontrolling interest	(4,741)							(4,741)
Common Stock, Shares, Outstanding at Mar. 31, 2020			62,772,978	24,656
Total equity at Mar. 31, 2020	$ 2,624,423	(207)	$ 62,773	$ (1,925)	1,652,861	838,841	(29,382)	101,255
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.535
Common Stock, Shares, Outstanding at Dec. 31, 2019			61,480,658	3,956
Total equity at Dec. 31, 2019	$ 2,464,069		$ 61,481	$ (267)	1,552,788	778,776	(30,655)	101,946
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	162,267
Other comprehensive income (loss), net of tax	3,733
Common Stock, Shares, Outstanding at Sep. 30, 2020			62,773,015	24,897
Total equity at Sep. 30, 2020	2,620,200		$ 62,773	$ (1,710)	1,655,912	828,993	(26,922)	101,154
Common Stock, Shares, Outstanding at Mar. 31, 2020			62,772,978	24,656
Total equity at Mar. 31, 2020	2,624,423	$ (207)	$ 62,773	$ (1,925)	1,652,861	838,841	(29,382)	101,255
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	24,694					20,966		3,728
Other comprehensive income (loss), net of tax	948						948
Dividends on Common Stock	(33,538)					(33,538)
Share-based compensation, shares			18	1,743
Share-based compensation	1,827			$ 46	1,781
Issuance costs	(79)				(79)
Distributions to noncontrolling interest	(3,779)							(3,779)
Common Stock, Shares, Outstanding at Jun. 30, 2020			62,772,996	26,399
Total equity at Jun. 30, 2020	$ 2,614,496		$ 62,773	$ (1,879)	1,654,563	826,269	(28,434)	101,204
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.535
Net income (loss)	$ 40,349					36,283		4,066
Other comprehensive income (loss), net of tax	1,512						1,512
Dividends on Common Stock	(33,559)					(33,559)
Share-based compensation, shares			19	(1,502)
Share-based compensation	1,637			$ 169	1,468
Issuance costs	(119)				(119)
Distributions to noncontrolling interest	(4,116)							(4,116)
Common Stock, Shares, Outstanding at Sep. 30, 2020			62,773,015	24,897
Total equity at Sep. 30, 2020	$ 2,620,200		$ 62,773	$ (1,710)	$ 1,655,912	$ 828,993	$ (26,922)	$ 101,154
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 0.535

Management's Statement:

9 Months Ended

Sep. 30, 2020

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 GAAP 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 included in our 2019 Annual Report on Form 10-K filed with the SEC.

Segment Reporting

We conduct our operations through the following reportable segments: Electric Utilities, Gas Utilities, Power Generation and Mining. Our reportable segments are based on our method of internal reporting, which is generally segregated by differences in products, services and regulation. All of our operations and assets are located within the United States.

Use of Estimates and Basis of Presentation

The information furnished in the accompanying Condensed Consolidated Financial Statements reflects certain estimates required and all adjustments, including accruals, which are, in the opinion of management, necessary for a fair presentation of the September 30, 2020, December 31, 2019 and September 30, 2019 financial information. 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. In particular, the normal peak usage season for electric utilities is June through August while the normal peak usage season for gas utilities is November through March. 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 September 30, 2020 and September 30, 2019, and our financial condition as of September 30, 2020 and December 31, 2019 are not necessarily indicative of the results of operations and financial condition to be expected for any other period. All earnings per share amounts discussed refer to diluted earnings per share unless otherwise noted.

Reclassification

We changed certain classifications of operating expenses on the Condensed Consolidated Statements of Income for the three and nine months ended September 30, 2019 to conform with current year presentation. The prior year reclassifications, which are shown in the table below, did not impact previously reported operating income or net income.


	Three Months Ended September 30, 2019		Nine Months Ended September 30, 2019
	(in millions)
Fuel, purchased power and cost of natural gas sold	$	0.5	$	1.8
Operations and maintenance	(0.5)		(1.8)
Operating income	$	—	$	—

COVID-19 Pandemic

In March 2020, the World Health Organization categorized COVID-19 as a pandemic and the President of the United States declared the outbreak a national emergency. The U.S. government has deemed electric and natural gas utilities to be critical infrastructure sectors that provide essential services during this emergency. As a provider of essential services, the Company has an obligation to provide services to our customers. The Company remains focused on protecting the health of our employees and the communities in which we operate while assuring the continuity of our business operations.

The Company’s Condensed Consolidated Financial Statements reflect estimates and assumptions made by management that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Condensed Consolidated Financial Statements and reported amounts of revenue and expenses during the reporting periods presented. The Company considered the impacts of COVID-19 on the assumptions and estimates used and determined that for the three and nine months ended September 30, 2020, there were no material adverse impacts on the Company’s results of operations.

Change in Accounting Principle - Pension Accounting Asset Method

Effective January 1, 2020, we changed our method of accounting for net periodic benefit cost. Prior to the change, the Company used a calculated value for determining market-related value of plan assets which amortized the effects of gains and losses over a five-year period. Effective with the accounting change, the Company will use a calculated value for the return-seeking assets (equities) in the portfolio and change to fair value for the liability-hedging assets (fixed income). See Note 12 for additional information.

Recently Issued Accounting Standards

Simplifying the Accounting for Income Taxes, ASU 2019-12

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes, as part of its overall simplification initiative to reduce costs and complexity in applying accounting standards while maintaining or improving the usefulness of the information provided to users of the financial statements. Amendments include removal of certain exceptions to the general principles of ASC 740, Income Taxes, and simplification in several other areas such as accounting for a franchise tax (or similar tax) that is partially based on income. The new guidance is effective for interim and annual periods beginning after December 15, 2020 with early adoption permitted. We are currently reviewing this standard to assess the impact on our financial position, results of operations and cash flows.

Recently Adopted Accounting Standards

Financial Instruments -- Credit Losses: Measurement of Credit Losses on Financial Instruments, ASU 2016-13

In June 2016, the FASB issued ASU 2016-13, Financial Instruments -- Credit Losses: Measurement of Credit Losses on Financial Instruments, which was subsequently amended by ASUs 2018-19, 2019-04, 2019-05, 2019-10, and 2019-11. The standard introduces new accounting guidance for credit losses on financial instruments within its scope, including trade receivables. This new guidance adds an impairment model that is based on expected losses rather than incurred losses.

We adopted this standard on January 1, 2020 with prior year comparative financial information remaining as previously reported when transitioning to the new standard. On January 1, 2020, we recorded an increase to our allowance for credit losses, primarily associated with the inclusion of expected losses on unbilled revenue. The cumulative effect of the adoption, net of tax impact, was $0.2 million, which was recorded as an adjustment to retained earnings.

Simplifying the Test for Goodwill Impairment, ASU 2017-04

In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment, by eliminating step 2 from the goodwill impairment test. Under the new guidance, if the carrying amount of a reporting unit exceeds its fair value, an impairment loss will be recognized in an amount equal to that excess, limited to the amount of goodwill allocated to that reporting unit. We adopted this standard prospectively on January 1, 2020. Adoption of this guidance did not have an impact on our financial position, results of operations or cash flows.

Internal-Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, ASU 2018-15

In August 2018, the FASB issued ASU 2018-15, Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for recording implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. As a result, certain categories of implementation costs that previously would have been charged to expense as incurred are now capitalized as prepayments and amortized over the term of the arrangement. We adopted this standard prospectively on January 1, 2020. Adoption of this guidance did not have a material impact on our financial position, results of operations or cash flows.

Revenue:

9 Months Ended

Sep. 30, 2020

Revenue from Contract with Customer [Abstract]

Revenue

Our revenue contracts generally provide for performance obligations that: are fulfilled and transfer control to customers over time; represent a series of distinct services that are substantially the same; involve the same pattern of transfer to the customer; and provide a right to consideration from our customers in an amount that corresponds directly with the value to the customer for the performance completed to date. Therefore, we recognize revenue in the amount to which we have a right to invoice. The following tables depict the disaggregation of revenue, including intercompany revenue, from contracts with customers by customer type and timing of revenue recognition for each of the reportable segments for the three and nine months ended September 30, 2020 and 2019. Sales tax and other similar taxes are excluded from revenues.


Three Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	169,505	$	94,367	$	—	$	14,668	$	(8,100)	$	270,440
Transportation	—		38,196		—		—		(139)		38,057
Wholesale	5,925		—		26,049		—		(24,521)		7,453
Market - off-system sales	9,535		36		—		—		(1,904)		7,667
Transmission/Other	15,653		10,277		—		—		(5,235)		20,695
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312
Other revenues	224		1,053		469		568		(36)		2,278
Total revenues	$	200,842	$	143,929	$	26,518	$	15,236	$	(39,935)	$	346,590

Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,668	$	(8,100)	$	6,568
Services transferred over time	200,618		142,876		26,049		—		(31,799)		337,744
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312


Three Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	162,214	$	89,810	$	—	$	14,992	$	(8,146)	$	258,870
Transportation	—		29,019		—		—		(195)		28,824
Wholesale	8,210		—		16,119		—		(14,414)		9,915
Market - off-system sales	6,452		139		—		—		(1,488)		5,103
Transmission/Other	14,274		10,965		—		—		(4,206)		21,033
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745
Other revenues	234		811		9,692		560		(9,494)		1,803
Total Revenues	$	191,384	$	130,744	$	25,811	$	15,552	$	(37,943)	$	325,548

Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,992	$	(8,146)	$	6,846
Services transferred over time	191,150		129,933		16,119		—		(20,303)		316,899
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745


Nine Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	459,949	$	513,208	$	—	$	43,917	$	(23,855)	$	993,219
Transportation	—		113,096		—		—		(416)		112,680
Wholesale	14,947		—		77,234		—		(72,609)		19,572
Market - off-system sales	17,940		197		—		—		(6,123)		12,014
Transmission/Other	43,271		32,038		—		—		(14,080)		61,229
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714
Other revenues	2,074		7,273		1,372		1,940		(819)		11,840
Total revenues	$	538,181	$	665,812	$	78,606	$	45,857	$	(117,902)	$	1,210,554

Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,917	$	(23,855)	$	20,062
Services transferred over time	536,107		658,539		77,234		—		(93,228)		1,178,652
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714


Nine Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	455,409	$	567,715	$	—	$	43,249	$	(23,315)	$	1,043,058
Transportation	—		102,159		—		—		(903)		101,256
Wholesale	23,334		—		46,650		—		(40,923)		29,061
Market - off-system sales	16,592		517		—		—		(5,047)		12,062
Transmission/Other	42,865		35,767		—		—		(12,608)		66,024
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461
Other revenues	2,465		1,135		29,114		1,777		(28,706)		5,785
Total Revenues	$	540,665	$	707,293	$	75,764	$	45,026	$	(111,502)	$	1,257,246

Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,249	$	(23,315)	$	19,934
Services transferred over time	538,200		706,158		46,650		—		(59,481)		1,231,527
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461

Contract Balances

The nature of our primary revenue contracts provides an unconditional right to consideration upon service delivery; therefore, no customer contract assets or liabilities exist. The unconditional right to consideration is represented by the balance in our Accounts Receivable further discussed in Note 4.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Business Segment Information:

9 Months Ended

Sep. 30, 2020

Segment Reporting Information, Additional Information [Abstract]

Business Segment Information

Our reportable segments are based on our method of internal reporting, which is generally segregated by differences in products, services and regulation. All of our operations and assets are located within the United States.

Segment and Corporate and Other information is as follows (in thousands):


Three Months Ended September 30, 2020	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	194,941	$	224	$	5,677	$	—	$	200,842
Gas Utilities	141,275		863		1,601		190		143,929
Power Generation	1,528		414		24,521		55		26,518
Mining	6,568		777		8,100		(209)		15,236
Inter-company eliminations	—		—		(39,899)		(36)		(39,935)
Total	$	344,312	$	2,278	$	—	$	—	$	346,590



Three Months Ended September 30, 2019	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	185,811	$	234	$	5,339	$	—	$	191,384
Gas Utilities	129,385		810		549		—		130,744
Power Generation	1,703		531		14,415		9,162		25,811
Mining	6,846		228		8,146		332		15,552
Inter-company eliminations	—		—		(28,449)		(9,494)		(37,943)
Total	$	323,745	$	1,803	$	—	$	—	$	325,548



Nine Months Ended September 30, 2020	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	518,641	$	2,074	$	17,466	$	—	$	538,181
Gas Utilities	655,386		7,083		3,153		190		665,812
Power Generation	4,625		1,206		72,609		166		78,606
Mining	20,062		1,477		23,855		463		45,857
Inter-company eliminations	—		—		(117,083)		(819)		(117,902)
Total	$	1,198,714	$	11,840	$	—	$	—	$	1,210,554



Nine Months Ended September 30, 2019	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	521,614	$	2,465	$	16,586	$	—	$	540,665
Gas Utilities	704,188		1,134		1,971		—		707,293
Power Generation	5,725		1,401		40,924		27,714		75,764
Mining	19,934		785		23,315		992		45,026
Inter-company eliminations	—		—		(82,796)		(28,706)		(111,502)
Total	$	1,251,461	$	5,785	$	—	$	—	$	1,257,246



	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Adjusted operating income (a):
Electric Utilities	$	52,083	$	50,653	$	121,726	$	125,219
Gas Utilities	18,147		4,736		139,253		116,607
Power Generation	8,738		11,822		31,489		33,945
Mining	3,505		3,374		9,992		9,351
Corporate and Other	(239)		(34)		(108)		(439)
Operating income	82,234		70,551		302,352		284,683

Interest expense, net	(36,041)		(33,487)		(107,039)		(102,469)
Impairment of investment	—		(19,741)		(6,859)		(19,741)
Other income (expense), net	(1,193)		580		(703)		55
Income tax (expense)	(4,651)		(2,508)		(25,484)		(22,078)
Net income	40,349		15,395		162,267		140,450
Net income attributable to noncontrolling interest	(4,066)		(3,655)		(11,844)		(10,319)
Net income available for common stock	$	36,283	$	11,740	$	150,423	$	130,131

__________

(a) Adjusted operating income recognizes inter-segment revenues and costs for Colorado Electric’s PPA with Black Hills Colorado IPP on an accrual basis rather than as a finance lease. This presentation of segment information does not impact consolidated financial results.

Segment and Corporate and Other balances included in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):


Total assets (net of inter-company eliminations) as of:	September 30, 2020		December 31, 2019
Segment:
Electric Utilities	$	3,040,064	$	2,900,983
Gas Utilities	4,201,325		4,032,339
Power Generation	403,491		417,715
Mining	75,752		77,175
Corporate and Other	108,418		130,245
Total assets	$	7,829,050	$	7,558,457

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details

Selected Balance Sheet Information:

9 Months Ended

Sep. 30, 2020

Selected Balance Sheet Information [Abstract]

Selected Balance Sheet Information

Accounts Receivable and Allowance for Credit Losses

Following is a summary of Accounts receivable, net included in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Accounts receivable, trade	$	108,351	$	144,747
Unbilled revenue	60,736		113,502
Less: Allowance for credit losses	(8,609)		(2,444)
Accounts receivable, net	$	160,478	$	255,805

Changes to allowance for credit losses for the nine months ended September 30, 2020 and 2019, respectively, were as follows (in thousands):


	Balance at Beginning of Year		Additions Charged to Costs and Expenses			Recoveries and Other Additions		Write-offs and Other Deductions		Balance at September 30,
2020	$	2,444	$	8,471	(a)	$	3,720	$	(6,026)	$	8,609
2019	$	3,209	$	5,637		$	2,742	$	(8,429)	$	3,159

__________

(a) Due to the COVID-19 pandemic, all of our jurisdictions temporarily suspended disconnections for a period of time, which increased our accounts receivable arrears balances. As a result, we increased our allowance for credit losses and bad debt expense for the nine months ended September 30, 2020 by an incremental $3.7 million.

The ongoing credit evaluation of our customers during the COVID-19 pandemic is further discussed in the Credit Risk section of Note 9.

Materials, Supplies and Fuel

The following amounts by major classification are included in Materials, supplies and fuel on the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Materials and supplies	$	93,069	$	82,809
Fuel - Electric Utilities	1,745		2,425
Natural gas in storage	31,544		31,938
Total materials, supplies and fuel	$	126,358	$	117,172

Accrued Liabilities

The following amounts by major classification are included in Accrued liabilities on the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Accrued employee compensation, benefits and withholdings	$	65,309	$	62,837
Accrued property taxes	40,624		44,547
Customer deposits and prepayments	59,510		54,728
Accrued interest	46,044		31,868
Other (none of which is individually significant)	32,523		32,787
Total accrued liabilities	$	244,010	$	226,767

Regulatory Matters:

9 Months Ended

Sep. 30, 2020

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Matters

We had the following regulatory assets and liabilities (in thousands) as of:



	September 30, 2020		December 31, 2019

Regulatory assets
Deferred energy and fuel cost adjustments (a)	$	35,878	$	34,088
Deferred gas cost adjustments (a)	3,670		1,540
Gas price derivatives (a)	499		3,328
Deferred taxes on AFUDC (b)	7,683		7,790
Employee benefit plan costs and related deferred taxes (c)	114,971		115,900
Environmental (a)	1,417		1,454

Loss on reacquired debt (a)	23,342		24,777
Renewable energy standard adjustment (a)	—		1,622
Deferred taxes on flow through accounting (c)	44,528		41,220
Decommissioning costs (b)	9,421		10,670
Gas supply contract termination (a)	4,027		8,485
Other regulatory assets (a)	25,800		20,470
Total regulatory assets	271,236		271,344
Less current regulatory assets	(49,493)		(43,282)
Regulatory assets, non-current	$	221,743	$	228,062

Regulatory liabilities
Deferred energy and gas costs (a)	$	14,443	$	17,278
Employee benefit plan costs and related deferred taxes (c)	40,719		43,349
Cost of removal (a)	169,426		166,727

Excess deferred income taxes (c)	286,055		285,438

Other regulatory liabilities (c)	16,956		23,860
Total regulatory liabilities	527,599		536,652
Less current regulatory liabilities	(22,282)		(33,507)
Regulatory liabilities, non-current	$	505,317	$	503,145

__________

(a) Recovery of costs, but we are not allowed a rate of return.

(b) In addition to recovery of costs, we are allowed a rate of return.

(c) In addition to recovery or repayment of costs, we are allowed a return on a portion of this amount or a reduction in rate base.

Regulatory Activity

Except as discussed below, there have been no other significant changes to our Regulatory Matters from those previously disclosed in Note 13 of the Notes to the Consolidated Financial Statements in our 2019 Annual Report on Form 10-K.

Colorado Gas

Rate Reviews and Jurisdictional Consolidation

On September 11, 2020, Colorado Gas filed a rate review with the CPUC seeking recovery on significant infrastructure investments in its 7,000-mile natural gas pipeline system. The rate review requests $13.5 million in new annual revenue with a capital structure of 50% equity and 50% debt and a return on equity of 9.95%. The request seeks to implement new rates in the second quarter of 2021. On September 11, 2020, in accordance with the final order from the earlier rate review discussed below, Colorado Gas also filed a new SSIR proposal that would recover safety-focused investments in its system over five years.

On February 1, 2019, Colorado Gas filed a rate review with the CPUC requesting $2.5 million in new revenue to recover investments in safety, reliability and system integrity and approval to consolidate rates, tariffs, and services of its two existing gas distribution territories. Colorado Gas also requested a new rider mechanism to recover future safety and integrity investments in its system. On May 19, 2020, the CPUC issued a final order which denied the system integrity recovery mechanism and consolidation of rate territories. In addition, the order resulted in an annual revenue decrease of $0.6 million and a return on equity of 9.2%. New rates were effective July 3, 2020.

TCJA

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the TCJA. The TCJA reduced the U.S. federal corporate tax rate from 35% to 21%. As such, the Company remeasured our deferred income taxes at the 21% federal tax rate as of December 31, 2017. In 2018, the Company successfully delivered the benefits from the TCJA to most of its utility customers.

In 2020, regulatory proceedings resolved the last of the Company’s open dockets seeking approval of its TCJA plans. As a result, the Company relieved certain TCJA-related liabilities, which resulted in an increase to net income for the three and nine months ended September 30, 2020 of $3.5 million and $4.0 million, respectively.

Nebraska Gas

Jurisdictional Consolidation and Rate Review

On June 1, 2020, Nebraska Gas filed a rate review with the NPSC to consolidate rate schedules into a new, single statewide structure and seek recovery on significant infrastructure investments in its 13,000-mile natural gas pipeline system. The rate review requests $17.3 million in new revenue with a capital structure of 50% equity and 50% debt and a return on equity of 10%. Nebraska statute allows for implementation of interim rates 90 days after filing a rate review and Nebraska Gas implemented interim rates effective on September 1, 2020. The request seeks to finalize rates in the first quarter of 2021. Nebraska Gas is also requesting an extension of its SSIR for five years to align the rider recovery mechanism across the consolidated utility.

Black Hills Wyoming and Wyoming Electric

Wygen I FERC Filing

On October 15, 2020, the FERC approved a settlement agreement that represents a resolution of all issues in the joint application filed by Wyoming Electric and Black Hills Wyoming on August 2, 2019 for approval of a new 60 MW PPA. Under the terms of the settlement, Wyoming Electric will continue to receive 60 MW of capacity and energy from the Wygen I power plant. The new agreement will commence on January 1, 2022, replace the existing PPA and continue for 11 years.

Earnings Per Share:

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Earnings Per Share

A reconciliation of share amounts used to compute earnings per share in the accompanying Condensed Consolidated Statements of Income was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019

Net income available for common stock	$	36,283	$	11,740	$	150,423	$	130,131

Weighted average shares - basic	62,575		60,976		62,310		60,458
Dilutive effect of:
Equity compensation	55		128		52		120
Weighted average shares - diluted	62,630		61,104		62,362		60,578

Earnings per share of common stock:
Earnings per share, Basic	$	0.58	$	0.19	$	2.41	$	2.15
Earnings per share, Diluted	$	0.58	$	0.19	$	2.41	$	2.15

The following securities were excluded from the diluted earnings per share computation because of their anti-dilutive nature (in thousands):


	Three Months Ended September 30,		Nine Months Ended September 30,
	2020	2019	2020	2019

Equity compensation	22	2	22	4
Restricted stock	49	—	40	1

Anti-dilutive shares	71	2	62	5

Notes Payable, Current Maturities and Debt:

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Notes Payable, Current Maturities and Debt

We had the following short-term debt outstanding in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020				December 31, 2019
	Balance Outstanding		Letters of Credit (a)		Balance Outstanding		Letters of Credit (a)
Revolving Credit Facility	$	—	$	24,588	$	—	$	30,274
CP Program	84,320		—		349,500		—
Total	$	84,320	$	24,588	$	349,500	$	30,274

_______________

(a) Letters of credit are off-balance sheet commitments that reduce the borrowing capacity available on our corporate Revolving Credit

Facility.

For the nine months ended September 30, 2020, we utilized a combination of our $750 million Revolving Credit Facility and CP Program to meet our business needs and support our capital investment plan. Our net short-term borrowings (payments) during the nine months ended September 30, 2020 were $(265) million.

Debt Covenants

Under our Revolving Credit Facility and term loan agreement, we are required to maintain a Consolidated Indebtedness to Capitalization Ratio not to exceed 0.65 to 1.00. Our Consolidated Indebtedness to Capitalization Ratio was calculated by dividing (i) consolidated indebtedness, which includes letters of credit and certain guarantees issued, by (ii) capital, which includes consolidated indebtedness plus consolidated net worth, which excludes noncontrolling interest in subsidiaries. Subject to applicable cure periods, a violation of any of these covenants would constitute an event of default that entitles the lenders to terminate their remaining commitments and accelerate all principal and interest outstanding.

Our Revolving Credit Facility and term loans require compliance with the following financial covenant, which we were in compliance with at September 30, 2020:

As of September 30, 2020

Covenant Requirement

Consolidated Indebtedness to Capitalization Ratio

59.3%

Less than

65%

Debt Offering

On June 17, 2020, we completed a public debt offering which consisted of $400 million of 2.50% 10-year senior unsecured notes due June 15, 2030. The proceeds were used to repay short-term debt and for working capital and general corporate purposes.

South Dakota Electric Series 94A Debt

On March 24, 2020, South Dakota Electric paid off its $2.9 million, Series 94A variable rate notes due June 1, 2024. These notes were tendered by the sole investor on March 17, 2020.

Equity:	9 Months Ended
Equity:	Sep. 30, 2020
Statement of Stockholders' Equity [Abstract]
Equity	Equity February 2020 Equity Issuance On February 27, 2020, we issued 1.2 million shares of common stock to a single investor through an underwritten registered transaction at a price of $81.77 per share for proceeds of $99 million, net of $1.0 million of issuance costs. The shares of common stock were offered pursuant to our shelf registration statement filed with the SEC. Shelf Registration, DRSPP and ATM Activity On August 3, 2020, we filed a shelf registration and DRSPP with the SEC. In conjunction with these shelf filings, we renewed the ATM. The renewed ATM program, which allows us to sell shares of our common stock, is the same as the prior program other than the aggregate value increased from $300 million to $400 million and a forward sales option was incorporated. Under the ATM, shares may be offered from time to time pursuant to a sales agreement dated August 3, 2020. Shares of common stock are offered pursuant to our shelf registration statement filed with the SEC. We did not issue any common shares under the ATM during the three and nine months ended September 30, 2020. During the three months ended September 30, 2019, we issued a total of 0.4 million shares of common stock under the ATM for proceeds of $30 million, net of $0.3 million in issuance costs. During the nine months ended September 30, 2019, we issued a total of 1.3 million shares of common stock under the ATM for proceeds of $99 million, net of $1.0 million in issuance costs.

Risk Management and Derivatives:

9 Months Ended

Sep. 30, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Risk Management and Derivatives

Market and Credit Risk Disclosures

Our activities in the regulated and non-regulated energy sectors expose us to a number of risks in the normal operations of our businesses. Depending on the activity, we are exposed to varying degrees of market risk and credit risk.

Market Risk

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

•Commodity price risk associated with our retail natural gas, wholesale electric power marketing activities and our fuel procurement for several of our gas-fired generation assets which include market fluctuations due to unpredictable factors such as the COVID-19 pandemic, weather, market speculation, pipeline constraints, and other factors that may impact natural gas and electric energy supply and demand; and

•Interest rate risk associated with future debt, including reduced access to liquidity during periods of extreme capital markets volatility, such as the 2008 financial crisis and the COVID-19 pandemic.

Credit Risk

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

We attempt to mitigate our credit exposure by conducting business primarily with high credit quality entities, 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, cash collateral requirements, letters of credit, and other security agreements.

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

We continue to monitor COVID-19 impacts and changes to customer load, consistency in customer payments, requests for deferred or discounted payments, and requests for changes to credit limits to quantify estimated future financial impacts to the allowance for credit losses. During the three and nine months ended September 30, 2020, the potential economic impact of the COVID-19 pandemic was considered in forward looking projections related to write-off and recovery rates, and resulted in increases to the allowance for credit losses and bad debt expense of $1.7 million and $3.7 million, respectively. See Note 4 for further information.

Derivatives and Hedging Activity

Our derivative and hedging activities included in the accompanying Condensed Consolidated Balance Sheets, Condensed Consolidated Statements of Income and Condensed Consolidated Statements of Comprehensive Income are detailed below and in Note 10.

Utilities

The operations of our utilities, including natural gas used by our Electric Utilities’ generation plants or those plants under PPAs where our Electric Utilities must provide the generation fuel (tolling agreements) and natural gas sold by our Gas Utilities, expose our utility customers to volatility in natural gas prices. Therefore, as allowed or required by state utility commissions, we have entered into commission-approved hedging programs utilizing natural gas futures, options, over-the-counter swaps 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, net of balance sheet offsetting as permitted by GAAP.

For our regulated utilities’ hedging plans, unrealized and realized gains and losses, as well as option premiums and commissions on these transactions, are recorded as Regulatory assets or Regulatory liabilities in the accompanying Condensed Consolidated Balance Sheets in accordance with the state utility commission guidelines. When the related costs are recovered through our rates, the hedging activity is recognized in the Condensed Consolidated Statements of Income.

We buy, sell and deliver natural gas at competitive prices by managing commodity price risk. As a result of these activities, this area of our business is exposed to risks associated with changes in the market price of natural gas. We manage our exposure to such risk using over-the-counter and exchange traded options and swaps with counterparties in anticipation of forecasted purchases and/or sales from October 2020 through May 2022. A portion of our over-the-counter swaps have been designated as cash flow hedges to mitigate the commodity price risk associated with deliveries under fixed price forward contracts to deliver gas to our Choice Gas Program customers. The gain or loss on these designated derivatives is reported in AOCI in the accompanying Condensed Consolidated Balance Sheets and reclassified into earnings in the same period that the underlying hedged item is recognized in earnings. Effectiveness of our hedging position is evaluated at least quarterly.

The contract or notional amounts and terms of the electric and natural gas derivative commodity instruments held at our utilities are composed of both long and short positions. We had the following net long positions as of:


		September 30, 2020		December 31, 2019
	Units	Notional Amounts	Maximum Term (months) (a)	Notional Amounts	Maximum Term (months) (a)
Natural gas futures purchased	MMBtus	1,930,000	6	1,450,000	12
Natural gas options purchased, net	MMBtus	8,320,000	6	3,240,000	3
Natural gas basis swaps purchased	MMBtus	1,780,000	6	1,290,000	12
Natural gas over-the-counter swaps, net (b)	MMBtus	4,525,100	20	4,600,000	24
Natural gas physical contracts, net (c)	MMBtus	23,350,287	13	13,548,235	12
Electric wholesale contracts (c)	MWh	55,225	3	—	0

__________

(a) Term reflects the maximum forward period hedged.

(b) As of September 30, 2020, 1,274,900 MMBtus of natural gas over-the-counter swaps purchases were designated as cash flow hedges.

We have certain derivative contracts which contain credit provisions. These credit provisions may require the Company to post collateral when credit exposure to the Company is in excess of a negotiated line of unsecured credit. At September 30, 2020, the Company posted $0.5 million related to such provisions, which is included in Other current assets on the Condensed Consolidated Balance Sheets.

Derivatives by Balance Sheet Classification

As required by accounting standards for derivatives and hedges, fair values within the following tables are presented on a gross basis aside from the netting of asset and liability positions. Netting of positions is permitted in accordance with accounting standards for offsetting and under terms of our master netting agreements that allow us to settle positive and negative positions.

The following table presents the fair value and balance sheet classification of our derivative instruments (in thousands) as of:


	Balance Sheet Location	September 30, 2020		December 31, 2019
Derivatives designated as hedges:
Asset derivative instruments:
Current commodity derivatives	Derivative assets, current	$	435	$	1
Noncurrent commodity derivatives	Other assets, non-current	94		3
Liability derivative instruments:
Current commodity derivatives	Derivative liabilities, current	(9)		(490)
Noncurrent commodity derivatives	Other deferred credits and other liabilities	—		(29)
Total derivatives designated as hedges		$	520	$	(515)

Derivatives not designated as hedges:
Asset derivative instruments:
Current commodity derivatives	Derivative assets, current	$	1,566	$	341
Noncurrent commodity derivatives	Other assets, non-current	434		2
Liability derivative instruments:
Current commodity derivatives	Derivative liabilities, current	(1,430)		(1,764)
Noncurrent commodity derivatives	Other deferred credits and other liabilities	—		(63)
Total derivatives not designated as hedges		$	570	$	(1,484)

Derivatives Designated as Hedges

The impacts of cash flow hedges on our Condensed Consolidated Statements of Comprehensive Income and Condensed Consolidated Statements of Income are presented below for the three and nine months ended September 30, 2020 and 2019. Note that this presentation does not reflect gains or losses arising from the underlying physical transactions; therefore, it is not indicative of the economic profit or loss we realized when the underlying physical and financial transactions were settled.


	Three Months Ended September 30,					Three Months Ended September 30,
	2020		2019			2020		2019
Derivatives in Cash Flow Hedging Relationships	Amount of (Gain)/Loss Recognized in OCI				Income Statement Location	Amount of Gain/(Loss) Reclassified from AOCI into Income
	(in thousands)					(in thousands)
Interest rate swaps	$	712	$	713	Interest expense	$	(712)	$	(713)
Commodity derivatives	691		(21)		Fuel, purchased power and cost of natural gas sold	(178)		(129)
Total	$	1,403	$	692		$	(890)	$	(842)


	Nine Months Ended September 30,					Nine Months Ended September 30,
	2020		2019			2020		2019
Derivatives in Cash Flow Hedging Relationships	Amount of (Gain)/Loss Recognized in OCI				Income Statement Location	Amount of Gain/(Loss) Reclassified from AOCI into Income
	(in thousands)					(in thousands)
Interest rate swaps	$	2,138	$	2,139	Interest expense	$	(2,138)	$	(2,139)
Commodity derivatives	959		(942)		Fuel, purchased power and cost of natural gas sold	(734)		508
Total	$	3,097	$	1,197		$	(2,872)	$	(1,631)

Based on September 30, 2020 prices, a $0.1 million gain would be realized, reported in pre-tax earnings and reclassified from AOCI during the next 12 months. As market prices fluctuate, estimated and actual realized gains or losses will change during future periods.

Derivatives Not Designated as Hedges

The following table summarizes the impacts of derivative instruments not designated as hedge instruments on our Condensed Consolidated Statements of Income for the three and nine months ended September 30, 2020 and 2019. Note that this presentation does not reflect gains or losses arising from the underlying physical transactions; therefore, it is not indicative of the economic profit or loss we realized when the underlying physical and financial transactions were settled.



		Three Months Ended September 30,
		2020		2019
Derivatives Not Designated as Hedging Instruments	Income Statement Location	Amount of Gain/(Loss) on Derivatives Recognized in Income

Commodity derivatives - Electric	Fuel, purchased power and cost of natural gas sold	$	(1,386)	$	—
Commodity derivatives - Electric	Other income (expense), net	—		142
Commodity derivatives - Natural Gas	Fuel, purchased power and cost of natural gas sold	1,777		(20)
		$	391	$	122


		Nine Months Ended September 30,
		2020		2019
Derivatives Not Designated as Hedging Instruments	Income Statement Location	Amount of Gain/(Loss) on Derivatives Recognized in Income
		(in thousands)
Commodity derivatives - Electric	Fuel, purchased power and cost of natural gas sold	$	(228)	$	—
Commodity derivatives - Electric	Other income (expense), net	—		142
Commodity derivatives - Natural Gas	Fuel, purchased power and cost of natural gas sold	2,992		(1,180)
		$	2,764	$	(1,038)

As discussed above, financial instruments used in our regulated utilities are not designated as cash flow hedges. There is no earnings impact for our Gas Utilities because the unrealized gains and losses arising from the use of these financial instruments are recorded as Regulatory assets or Regulatory liabilities. The net unrealized losses included in our Regulatory asset or Regulatory liability accounts related to these derivatives in our Gas Utilities were $0.5 million and $3.3 million as of September 30, 2020 and December 31, 2019, respectively. For our Electric Utilities, the unrealized gains and losses arising from these derivatives are recognized in the Condensed Consolidated Statements of Income.

Fair Value Measurements:

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

We use the following fair value hierarchy for determining inputs for our financial instruments. Our assets and liabilities for financial instruments are classified and disclosed in one of the following fair value categories:

Level 1 — Unadjusted quoted prices available in active markets that are accessible at the measurement date for identical unrestricted assets or liabilities. Level 1 instruments primarily consist of highly liquid and actively traded financial instruments with quoted pricing information on an ongoing basis;

Level 2 — Pricing inputs include quoted prices for identical or similar assets and liabilities in active markets other than quoted prices in Level 1, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and inputs that are derived principally from or corroborated by observable market data by correlation or other means; and

Level 3 — Pricing inputs are generally less observable from objective sources. These inputs reflect management’s best estimate of fair value using its own assumptions about the assumptions a market participant would use in pricing the asset or liability.

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 when the time between the valuation date and the delivery date of a transaction becomes shorter, positively impacting the availability of observable pricing inputs.

Recurring Fair Value Measurements

Derivatives

The commodity contracts for our Utilities segments are valued using the market approach and include forward strip pricing at liquid delivery points, exchange-traded futures, options, basis swaps and over-the-counter swaps and options (Level 2) for wholesale electric energy and natural gas contracts. For exchange-traded futures, options and basis swap assets and liabilities, fair value was derived using broker quotes validated by the exchange settlement pricing for the applicable contract. For over-the-counter instruments, the fair value is obtained by utilizing a nationally recognized service that obtains observable inputs to compute the fair value, which we validate by comparing our valuation with the counterparty. The fair value of these swaps includes a CVA based on the credit spreads of the counterparties when we are in an unrealized gain position or on our own credit spread when we are in an unrealized loss position. For additional information, see Note 1 to the Consolidated Financial Statements included in our 2019 Annual Report on Form 10-K filed with the SEC.


	As of September 30, 2020
	Level 1		Level 2		Level 3		Cash Collateral and Counterparty Netting		Total
	(in thousands)
Assets:
Commodity derivatives — Gas Utilities	$	—	$	6,544	$	—	$	(4,015)	$	2,529
Commodity derivatives — Electric Utilities	—		—		—		—		—
Total	$	—	$	6,544	$	—	$	(4,015)	$	2,529

Liabilities:
Commodity derivatives — Gas Utilities	$	—	$	1,537	$	—	$	(326)	$	1,211
Commodity derivatives — Electric Utilities	—		228		—		—		$	228
Total	$	—	$	1,765	$	—	$	(326)	$	1,439


	As of December 31, 2019
	Level 1		Level 2		Level 3		Cash Collateral and Counterparty Netting		Total
	(in thousands)
Assets:
Commodity derivatives — Gas Utilities	$	—	$	1,433	$	—	$	(1,085)	$	348
Total	$	—	$	1,433	$	—	$	(1,085)	$	348

Liabilities:
Commodity derivatives — Gas Utilities	$	—	$	5,254	$	—	$	(2,909)	$	2,345
Total	$	—	$	5,254	$	—	$	(2,909)	$	2,345

Pension and Postretirement Plan Assets

Fair value measurements also apply to the valuation of our pension and postretirement plan assets. Current accounting guidance requires employers to annually disclose information about the fair value measurements of their assets of a defined benefit pension or other postretirement plan. The fair value of these assets is presented in Note 18 to the Consolidated Financial Statements included in our 2019 Annual Report on Form 10-K. The Company has concluded that the market volatility associated with COVID-19 does not require interim re-measurement of our pension plan assets or defined benefit obligations. See Note 12 for additional information.

Nonrecurring Fair Value Measurement

A discussion of the fair value of our investment in equity securities of a privately held oil and gas company, a Level 3 asset, is included in Note 15.

Other Fair Value Measures

The following table presents the carrying amounts and fair values of financial instruments not recorded at fair value on the Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020				December 31, 2019
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term debt, including current maturities (a)	$	3,536,765	$	4,177,801	$	3,145,839	$	3,479,367

__________

(a) Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified as Level 2 in the fair value hierarchy. Carrying amount of long-term debt is net of deferred financing costs.

Other Comprehensive Income (Loss):

9 Months Ended

Sep. 30, 2020

Statement of Comprehensive Income [Abstract]

Other Comprehensive Income (Loss)

We record deferred gains (losses) in AOCI related to interest rate swaps designated as cash flow hedges, commodity contracts designated as cash flow hedges and the amortization of components of our defined benefit plans. Deferred gains (losses) for our commodity contracts designated as cash flow hedges are recognized in earnings upon settlement, while deferred gains (losses) related to our interest rate swaps are recognized in earnings as they are amortized.

The following table details reclassifications out of AOCI and into net income. The amounts in parentheses below indicate decreases to net income in the Condensed Consolidated Statements of Income for the period (in thousands):


	Location on the Condensed Consolidated Statements of Income	Amount Reclassified from AOCI
		Three Months Ended September 30,				Nine Months Ended September 30,
		2020		2019		2020		2019
Gains and (losses) on cash flow hedges:
Interest rate swaps	Interest expense	$	(712)	$	(713)	$	(2,138)	$	(2,139)
Commodity contracts	Fuel, purchased power and cost of natural gas sold	(178)		(129)		(734)		508
		(890)		(842)		(2,872)		(1,631)
Income tax	Income tax benefit (expense)	209		170		680		358
Total reclassification adjustments related to cash flow hedges, net of tax		$	(681)	$	(672)	$	(2,192)	$	(1,273)

Amortization of components of defined benefit plans:
Prior service cost	Operations and maintenance	$	24	$	19	$	79	$	58

Actuarial gain (loss)	Operations and maintenance	(597)		(83)		(1,791)		(524)
		(573)		(64)		(1,712)		(466)
Income tax	Income tax benefit (expense)	143		89		407		184
Total reclassification adjustments related to defined benefit plans, net of tax		$	(430)	$	25	$	(1,305)	$	(282)
Total reclassifications		$	(1,111)	$	(647)	$	(3,497)	$	(1,555)

Balances by classification included within AOCI, net of tax on the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):


	Interest Rate Swaps		Commodity Derivatives		Employee Benefit Plans		Total
As of December 31, 2019	$	(15,122)	$	(456)	$	(15,077)	$	(30,655)
Other comprehensive income (loss)
before reclassifications	—		181		55		236
Amounts reclassified from AOCI	1,630		562		1,305		3,497
As of September 30, 2020	$	(13,492)	$	287	$	(13,717)	$	(26,922)


	Interest Rate Swaps		Commodity Derivatives		Employee Benefit Plans		Total
As of December 31, 2018	$	(17,307)	$	328	$	(9,937)	$	(26,916)
Other comprehensive income (loss)
before reclassifications	—		(334)		—		(334)
Amounts reclassified from AOCI	1,639		(366)		282		1,555
As of September 30, 2019	$	(15,668)	$	(372)	$	(9,655)	$	(25,695)

Employee Benefit Plans:

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Employee Benefit Plans

Change in Accounting Principle - Pension Accounting Asset Method

Effective January 1, 2020, the Company changed its method of accounting for net periodic benefit cost. Prior to the change, the Company used a calculated value for determining market-related value of plan assets which amortized the effects of gains and losses over a five-year period. Effective with the accounting change, the Company will use a calculated value for the return-seeking assets (equities) in the portfolio and fair value for the liability-hedging assets (fixed income). The Company considers the fair value method for determining market-related value of liability-hedging assets to be a preferable method of accounting because asset-related gains and losses are subject to amortization into pension cost immediately. Additionally, the fair value for liability-hedging assets allows for the impact of gains and losses on this portion of the asset portfolio to be reflected in tandem with changes in the liability which is linked to changes in the discount rate assumption for re-measurement.

We evaluated the effect of this change in accounting method and deemed it immaterial to the historical and current financial statements and therefore did not account for the change retrospectively. Accordingly, the Company calculated the cumulative difference using a calculated value versus fair value to determine market-related value for liability-hedging assets of the portfolio. The cumulative effect of this change, as of January 1, 2020, resulted in a decrease to prior service costs, as recorded in Other income (expense), net, of $0.6 million, an increase in Income tax expense of $0.2 million and an increase to Net income of $0.4 million within the accompanying Condensed Consolidated Statements of Income for the nine months ended September 30, 2020.

Funding Status of Employee Benefit Plans

Based on the fair value of assets and estimated discount rate used to value benefit obligations as of September 30, 2020, we estimate the unfunded status of our employee benefit plans to be approximately $51 million compared to $51 million at December 31, 2019. In 2012, we froze our pension plan and closed it to new participants. Since then, we have implemented various de-risking strategies including lump sum buyouts, the purchase of annuities and the reduction of return-seeking assets over time to a more liability-hedged portfolio. As a result, recent capital markets volatility driven by the COVID-19 pandemic has not materially affected our unfunded status and does not require interim re-measurement of our pension plan assets or defined benefit obligations.

Defined Benefit Pension Plan

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


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	1,352	$	1,346	$	4,058	$	4,037
Interest cost	3,356		4,344		10,069		13,031
Expected return on plan assets	(5,647)		(6,100)		(16,943)		(18,300)
Prior service cost (benefit)	—		6		—		19
Net loss (gain)	2,093		941		6,279		2,822
Net periodic benefit cost	$	1,154	$	537	$	3,463	$	1,609

Defined Benefit Postretirement Healthcare Plan

The components of net periodic benefit cost for the Defined Benefit Postretirement Healthcare Plan were as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	514	$	454	$	1,542	$	1,362
Interest cost	412		560		1,237		1,683
Expected return on plan assets	(46)		(57)		(137)		(172)
Prior service cost (benefit)	(136)		(99)		(410)		(298)
Net loss (gain)	5		—		15		—
Net periodic benefit cost	$	749	$	858	$	2,247	$	2,575

Supplemental Non-qualified Defined Benefit and Defined Contribution Plans

The components of net periodic benefit cost for the Supplemental Non-qualified Defined Benefit and Defined Contribution Plans were as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	1,035	$	429	$	1,482	$	2,406
Interest cost	274		324		824		972
Prior service cost (benefit)	1		—		1		1
Net loss (gain)	425		134		1,277		402
Net periodic benefit cost	$	1,735	$	887	$	3,584	$	3,781

Contributions

Contributions to the Defined Benefit Pension Plan are cash contributions made directly to the Pension Plan Trust account. Contributions to the Postretirement Healthcare and Supplemental Plans are made in the form of benefit payments. Contributions made in the first nine months of 2020 and anticipated contributions for 2020 and 2021 are as follows (in thousands):


	Contributions Made		Additional Contributions		Contributions
	Nine Months Ended September 30, 2020		Anticipated for 2020		Anticipated for 2021
Defined Benefit Pension Plan	$	12,700	$	—	$	12,700
Non-pension Defined Benefit Postretirement Healthcare Plans	$	4,006	$	1,335	$	5,227
Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	1,065	$	355	$	1,964

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section S99
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=21916913&loc=d3e273930-122802

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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+ Details

Commitments and Contingencies:	9 Months Ended
Commitments and Contingencies:	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
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 2019 Annual Report on Form 10-K except for those described below and in Note 5. Power Sales Agreement - Colorado Electric On July 1, 2020, Colorado Electric entered into a PSA with the City of Colorado Springs to sell up to 60 MW of wind energy purchased from PRPA under a separate 60 MW PPA transacted on June 26, 2019. This PSA with the City of Colorado Springs expires June 30, 2025. Power Purchase Agreement - South Dakota Electric On September 11, 2020, South Dakota Electric entered into a PPA with Fall River Solar, LLC to purchase up to 80 MW of renewable energy upon construction completion of a new solar facility which is expected by the end of 2022. This agreement will expire 20 years after construction completion.

Income Taxes:	9 Months Ended
Income Taxes:	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes CARES Act On March 27, 2020, the President signed the CARES Act, which contained, in part, an allowance for deferral of the employer portion of Social Security employment tax liabilities until 2021 and 2022, as well as a COVID-19 employee retention tax credit of up to $5,000 per eligible employee. Eligible employers are taxpayers experiencing either: (1) a full or partial suspension of business operations stemming from a government COVID-19 related order or (2) a more than 50% drop in gross receipts compared to the corresponding calendar quarter in 2019. This 50% employee retention tax credit applies up to $10,000 in qualified wages paid between March 13, 2020 through December 31, 2020, and is refundable to the extent it exceeds the employer portion of payroll tax liability. Eligible wages or employer-paid health benefits must be paid for the period of time during which an employee did not provide services. However, employees do not need to stop providing all services to the employer for the credit to potentially apply. Additionally, the CARES Act accelerates the amount of alternative minimum tax (“AMT”) credits that can be refunded for the 2018 and 2019 annual tax returns. In 2020, we filed for, and received, a refund of approximately $2.4 million of AMT credit carryforwards under this provision. During the three and nine months ended September 30, 2020, we utilized the payroll tax deferral provision which allowed us to defer payment of approximately $4.0 million and $6.9 million, respectively, of Social Security employment tax liabilities. We are currently reviewing the potential future benefits of the CARES Act related to employee retention tax credits to assess the impact on our financial position, results of operations and cash flows. Income tax (expense) for the Three Months Ended September 30, 2020 Compared to the Three Months Ended September 30, 2019. Income tax (expense) for the three months ended September 30, 2020 was $(4.7) million compared to $(2.5) million reported for the same period in 2019. For the three months ended September 30, 2020, the effective tax rate was 10.3% compared to 14.0% for the same period in 2019. The lower effective tax rate is primarily due to increased tax benefits from federal production tax credits associated with new wind assets and reversal of accrued excess deferred income taxes as part of resolving the last of the Company’s open dockets seeking approval of its TCJA plans as discussed in Note 5. Income tax (expense) for the Nine Months Ended September 30, 2020 Compared to the Nine Months Ended September 30, 2019. Income tax (expense) for the nine months ended September 30, 2020 was $(25) million compared to $(22) million reported for the same period in 2019. The effective tax rate was 13.6% for both the nine months ended September 30, 2020 and 2019, primarily due to increased tax benefits from forecasted federal production tax credits associated with new wind assets and reversal of accrued excess deferred income taxes as part of resolving the last of the Company’s open dockets seeking approval of its TCJA plans as discussed in Note 5 offset by a prior year discrete tax benefit related to repairs and certain indirect costs.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Investments:

9 Months Ended

Sep. 30, 2020

Investments, All Other Investments [Abstract]

Investments

In February 2018, we contributed $28 million of assets in exchange for equity securities in a privately held oil and gas company as we divested our Oil and Gas segment. The carrying value of our investment in the equity securities was recorded at cost. We review this investment on a periodic basis to determine whether a significant event or change in circumstances has occurred that may have an adverse effect on the value of the investment.

During the third quarter of 2019, we assessed our investment for impairment as a result of a deterioration in earnings performance of the privately held oil and gas company and an adverse change in future natural gas prices. We engaged a third-party valuation consultant to estimate the fair value of our investment. The valuation was primarily based on an income approach but also considered a market valuation approach. The significant inputs used to estimate the fair value were the oil and gas reserve quantities and values utilizing forward market price curves, industry standard reserve adjustment factors and a discount rate of 10%. Based on the results of the valuation, we concluded that the carrying value of the investment exceeded fair value. As a result, we recorded a pre-tax impairment loss of $20 million for the three months ended September 30, 2019, which was the difference between the carrying value and the fair value of the investment at that time.

During the first quarter of 2020, we assessed our investment for impairment as a result of continued adverse changes in future natural gas prices and liquidity concerns at the privately held oil and gas company. We performed an internal analysis to compute the fair value of our investment, utilizing a consistent methodology as applied during the third quarter of 2019. Based on the results of the valuation, we concluded that the carrying value of the investment exceeded fair value. As a result, we recorded a pre-tax impairment loss of $6.9 million for the three months ended March 31, 2020, which was the difference between the carrying value and the fair value of the investment at that time.

The following table presents the carrying value of our investments (in thousands) as of:


	September 30, 2020		December 31, 2019
Investment in privately held oil and gas company	$	1,500	$	8,359
Cash surrender value of life insurance contracts	13,467		13,056
Other investments	692		514
Total investments	$	15,659	$	21,929

Subsequent Events:	9 Months Ended
Subsequent Events:	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsWe evaluated all subsequent event activity and concluded that no subsequent events have occurred that would require recognition in the condensed consolidated financial statements or disclosures, with the exception of those items disclosed in Note 5

Management's Statement (Policies)

9 Months Ended

Sep. 30, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Segment Reporting

Use of Estimates and Basis of Presentation

Reclassification


	Three Months Ended September 30, 2019		Nine Months Ended September 30, 2019
	(in millions)
Fuel, purchased power and cost of natural gas sold	$	0.5	$	1.8
Operations and maintenance	(0.5)		(1.8)
Operating income	$	—	$	—

Change in Accounting Principle - Pension Accounting Asset Method

Recently Issued and Adopted Accounting Standards

Recently Issued Accounting Standards

Simplifying the Accounting for Income Taxes, ASU 2019-12

Recently Adopted Accounting Standards

Financial Instruments -- Credit Losses: Measurement of Credit Losses on Financial Instruments, ASU 2016-13

Simplifying the Test for Goodwill Impairment, ASU 2017-04

Internal-Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, ASU 2018-15

Revenue Recognition

Our revenue contracts generally provide for performance obligations that: are fulfilled and transfer control to customers over time; represent a series of distinct services that are substantially the same; involve the same pattern of transfer to the customer; and provide a right to consideration from our customers in an amount that corresponds directly with the value to the customer for the performance completed to date. Therefore, we recognize revenue in the amount to which we have a right to invoice. The nature of our primary revenue contracts provides an unconditional right to consideration upon service delivery; therefore, no customer contract assets or liabilities exist. The unconditional right to consideration is represented by the balance in our Accounts Receivable further discussed in Note 4.

- Definition

Disclosure of accounting policy for pension and other postretirement benefit plans. This accounting policy may address (1) the types of plans sponsored by the entity, and the benefits provided by each plan (2) groups that participate in (or are covered by) each plan (3) how plan assets, liabilities and expenses are measured, including the use of any actuaries and (4) significant assumptions used by the entity to value plan assets and liabilities and how such assumptions are derived.

+ References + Details

- Definition

Disclosure of accounting policy for segment reporting.

+ References + Details

Organization, Consolidation and Presentation of Financial Statements (Tables)

9 Months Ended

Sep. 30, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Reclassification

The prior year reclassifications, which are shown in the table below, did not impact previously reported operating income or net income.


	Three Months Ended September 30, 2019		Nine Months Ended September 30, 2019
	(in millions)
Fuel, purchased power and cost of natural gas sold	$	0.5	$	1.8
Operations and maintenance	(0.5)		(1.8)
Operating income	$	—	$	—

Revenue (Tables)

9 Months Ended

Sep. 30, 2020

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following tables depict the disaggregation of revenue, including intercompany revenue, from contracts with customers by customer type and timing of revenue recognition for each of the reportable segments for the three and nine months ended September 30, 2020 and 2019. Sales tax and other similar taxes are excluded from revenues.


Three Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	169,505	$	94,367	$	—	$	14,668	$	(8,100)	$	270,440
Transportation	—		38,196		—		—		(139)		38,057
Wholesale	5,925		—		26,049		—		(24,521)		7,453
Market - off-system sales	9,535		36		—		—		(1,904)		7,667
Transmission/Other	15,653		10,277		—		—		(5,235)		20,695
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312
Other revenues	224		1,053		469		568		(36)		2,278
Total revenues	$	200,842	$	143,929	$	26,518	$	15,236	$	(39,935)	$	346,590

Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,668	$	(8,100)	$	6,568
Services transferred over time	200,618		142,876		26,049		—		(31,799)		337,744
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312


Three Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	162,214	$	89,810	$	—	$	14,992	$	(8,146)	$	258,870
Transportation	—		29,019		—		—		(195)		28,824
Wholesale	8,210		—		16,119		—		(14,414)		9,915
Market - off-system sales	6,452		139		—		—		(1,488)		5,103
Transmission/Other	14,274		10,965		—		—		(4,206)		21,033
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745
Other revenues	234		811		9,692		560		(9,494)		1,803
Total Revenues	$	191,384	$	130,744	$	25,811	$	15,552	$	(37,943)	$	325,548

Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,992	$	(8,146)	$	6,846
Services transferred over time	191,150		129,933		16,119		—		(20,303)		316,899
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745


Nine Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	459,949	$	513,208	$	—	$	43,917	$	(23,855)	$	993,219
Transportation	—		113,096		—		—		(416)		112,680
Wholesale	14,947		—		77,234		—		(72,609)		19,572
Market - off-system sales	17,940		197		—		—		(6,123)		12,014
Transmission/Other	43,271		32,038		—		—		(14,080)		61,229
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714
Other revenues	2,074		7,273		1,372		1,940		(819)		11,840
Total revenues	$	538,181	$	665,812	$	78,606	$	45,857	$	(117,902)	$	1,210,554

Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,917	$	(23,855)	$	20,062
Services transferred over time	536,107		658,539		77,234		—		(93,228)		1,178,652
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714


Nine Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	455,409	$	567,715	$	—	$	43,249	$	(23,315)	$	1,043,058
Transportation	—		102,159		—		—		(903)		101,256
Wholesale	23,334		—		46,650		—		(40,923)		29,061
Market - off-system sales	16,592		517		—		—		(5,047)		12,062
Transmission/Other	42,865		35,767		—		—		(12,608)		66,024
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461
Other revenues	2,465		1,135		29,114		1,777		(28,706)		5,785
Total Revenues	$	540,665	$	707,293	$	75,764	$	45,026	$	(111,502)	$	1,257,246

Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,249	$	(23,315)	$	19,934
Services transferred over time	538,200		706,158		46,650		—		(59,481)		1,231,527
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461

Business Segment Information (Tables)

9 Months Ended

Sep. 30, 2020

Segment Reporting Information, Additional Information [Abstract]

Segment Reporting

Segment and Corporate and Other information is as follows (in thousands):


Three Months Ended September 30, 2020	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	194,941	$	224	$	5,677	$	—	$	200,842
Gas Utilities	141,275		863		1,601		190		143,929
Power Generation	1,528		414		24,521		55		26,518
Mining	6,568		777		8,100		(209)		15,236
Inter-company eliminations	—		—		(39,899)		(36)		(39,935)
Total	$	344,312	$	2,278	$	—	$	—	$	346,590



Three Months Ended September 30, 2019	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	185,811	$	234	$	5,339	$	—	$	191,384
Gas Utilities	129,385		810		549		—		130,744
Power Generation	1,703		531		14,415		9,162		25,811
Mining	6,846		228		8,146		332		15,552
Inter-company eliminations	—		—		(28,449)		(9,494)		(37,943)
Total	$	323,745	$	1,803	$	—	$	—	$	325,548



Nine Months Ended September 30, 2020	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	518,641	$	2,074	$	17,466	$	—	$	538,181
Gas Utilities	655,386		7,083		3,153		190		665,812
Power Generation	4,625		1,206		72,609		166		78,606
Mining	20,062		1,477		23,855		463		45,857
Inter-company eliminations	—		—		(117,083)		(819)		(117,902)
Total	$	1,198,714	$	11,840	$	—	$	—	$	1,210,554



Nine Months Ended September 30, 2019	External Operating Revenue				Inter-company Operating Revenue				Total Revenues
	Contract Customers		Other Revenues		Contract Customers		Other Revenues
Segment:
Electric Utilities	$	521,614	$	2,465	$	16,586	$	—	$	540,665
Gas Utilities	704,188		1,134		1,971		—		707,293
Power Generation	5,725		1,401		40,924		27,714		75,764
Mining	19,934		785		23,315		992		45,026
Inter-company eliminations	—		—		(82,796)		(28,706)		(111,502)
Total	$	1,251,461	$	5,785	$	—	$	—	$	1,257,246



	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Adjusted operating income (a):
Electric Utilities	$	52,083	$	50,653	$	121,726	$	125,219
Gas Utilities	18,147		4,736		139,253		116,607
Power Generation	8,738		11,822		31,489		33,945
Mining	3,505		3,374		9,992		9,351
Corporate and Other	(239)		(34)		(108)		(439)
Operating income	82,234		70,551		302,352		284,683

Interest expense, net	(36,041)		(33,487)		(107,039)		(102,469)
Impairment of investment	—		(19,741)		(6,859)		(19,741)
Other income (expense), net	(1,193)		580		(703)		55
Income tax (expense)	(4,651)		(2,508)		(25,484)		(22,078)
Net income	40,349		15,395		162,267		140,450
Net income attributable to noncontrolling interest	(4,066)		(3,655)		(11,844)		(10,319)
Net income available for common stock	$	36,283	$	11,740	$	150,423	$	130,131

__________

Reconciliation of Assets from Segment to Consolidated

Segment and Corporate and Other balances included in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):


Total assets (net of inter-company eliminations) as of:	September 30, 2020		December 31, 2019
Segment:
Electric Utilities	$	3,040,064	$	2,900,983
Gas Utilities	4,201,325		4,032,339
Power Generation	403,491		417,715
Mining	75,752		77,175
Corporate and Other	108,418		130,245
Total assets	$	7,829,050	$	7,558,457

Selected Balance Sheet Information (Tables)

9 Months Ended

Sep. 30, 2020

Selected Balance Sheet Information [Abstract]

Account Receivable Schedule

Following is a summary of Accounts receivable, net included in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Accounts receivable, trade	$	108,351	$	144,747
Unbilled revenue	60,736		113,502
Less: Allowance for credit losses	(8,609)		(2,444)
Accounts receivable, net	$	160,478	$	255,805

Financing Receivable, Current, Allowance for Credit Loss

Changes to allowance for credit losses for the nine months ended September 30, 2020 and 2019, respectively, were as follows (in thousands):


	Balance at Beginning of Year		Additions Charged to Costs and Expenses			Recoveries and Other Additions		Write-offs and Other Deductions		Balance at September 30,
2020	$	2,444	$	8,471	(a)	$	3,720	$	(6,026)	$	8,609
2019	$	3,209	$	5,637		$	2,742	$	(8,429)	$	3,159

Materials, Supplies, and Fuel Schedule

The following amounts by major classification are included in Materials, supplies and fuel on the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Materials and supplies	$	93,069	$	82,809
Fuel - Electric Utilities	1,745		2,425
Natural gas in storage	31,544		31,938
Total materials, supplies and fuel	$	126,358	$	117,172

Accrued Liabilities Schedule

The following amounts by major classification are included in Accrued liabilities on the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020		December 31, 2019
Accrued employee compensation, benefits and withholdings	$	65,309	$	62,837
Accrued property taxes	40,624		44,547
Customer deposits and prepayments	59,510		54,728
Accrued interest	46,044		31,868
Other (none of which is individually significant)	32,523		32,787
Total accrued liabilities	$	244,010	$	226,767

Regulatory Matters (Tables)

9 Months Ended

Sep. 30, 2020

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets and Liabilities

We had the following regulatory assets and liabilities (in thousands) as of:



	September 30, 2020		December 31, 2019

Regulatory assets
Deferred energy and fuel cost adjustments (a)	$	35,878	$	34,088
Deferred gas cost adjustments (a)	3,670		1,540
Gas price derivatives (a)	499		3,328
Deferred taxes on AFUDC (b)	7,683		7,790
Employee benefit plan costs and related deferred taxes (c)	114,971		115,900
Environmental (a)	1,417		1,454

Loss on reacquired debt (a)	23,342		24,777
Renewable energy standard adjustment (a)	—		1,622
Deferred taxes on flow through accounting (c)	44,528		41,220
Decommissioning costs (b)	9,421		10,670
Gas supply contract termination (a)	4,027		8,485
Other regulatory assets (a)	25,800		20,470
Total regulatory assets	271,236		271,344
Less current regulatory assets	(49,493)		(43,282)
Regulatory assets, non-current	$	221,743	$	228,062

Regulatory liabilities
Deferred energy and gas costs (a)	$	14,443	$	17,278
Employee benefit plan costs and related deferred taxes (c)	40,719		43,349
Cost of removal (a)	169,426		166,727

Excess deferred income taxes (c)	286,055		285,438

Other regulatory liabilities (c)	16,956		23,860
Total regulatory liabilities	527,599		536,652
Less current regulatory liabilities	(22,282)		(33,507)
Regulatory liabilities, non-current	$	505,317	$	503,145

__________

(a) Recovery of costs, but we are not allowed a rate of return.

(b) In addition to recovery of costs, we are allowed a rate of return.

(c) In addition to recovery or repayment of costs, we are allowed a return on a portion of this amount or a reduction in rate base.

Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Schedule of Earnings Per Share Reconciliation

A reconciliation of share amounts used to compute earnings per share in the accompanying Condensed Consolidated Statements of Income was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019

Net income available for common stock	$	36,283	$	11,740	$	150,423	$	130,131

Weighted average shares - basic	62,575		60,976		62,310		60,458
Dilutive effect of:
Equity compensation	55		128		52		120
Weighted average shares - diluted	62,630		61,104		62,362		60,578

Earnings per share of common stock:
Earnings per share, Basic	$	0.58	$	0.19	$	2.41	$	2.15
Earnings per share, Diluted	$	0.58	$	0.19	$	2.41	$	2.15

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following securities were excluded from the diluted earnings per share computation because of their anti-dilutive nature (in thousands):


	Three Months Ended September 30,		Nine Months Ended September 30,
	2020	2019	2020	2019

Equity compensation	22	2	22	4
Restricted stock	49	—	40	1

Anti-dilutive shares	71	2	62	5

Notes Payable, Current Maturities and Debt (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Schedule of Short-term Debt

We had the following short-term debt outstanding in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020				December 31, 2019
	Balance Outstanding		Letters of Credit (a)		Balance Outstanding		Letters of Credit (a)
Revolving Credit Facility	$	—	$	24,588	$	—	$	30,274
CP Program	84,320		—		349,500		—
Total	$	84,320	$	24,588	$	349,500	$	30,274

_______________

(a) Letters of credit are off-balance sheet commitments that reduce the borrowing capacity available on our corporate Revolving Credit

Facility.

Credit Facility and Short Term Debt Covenants

Our Revolving Credit Facility and term loans require compliance with the following financial covenant, which we were in compliance with at September 30, 2020:

As of September 30, 2020

Covenant Requirement

Consolidated Indebtedness to Capitalization Ratio

59.3%

Less than

65%

Risk Management and Derivatives (Tables)

9 Months Ended

Sep. 30, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Contract or Notional Amounts and Terms of Marketing Activities and Derivative Commodity Instruments

We had the following net long positions as of:


		September 30, 2020		December 31, 2019
	Units	Notional Amounts	Maximum Term (months) (a)	Notional Amounts	Maximum Term (months) (a)
Natural gas futures purchased	MMBtus	1,930,000	6	1,450,000	12
Natural gas options purchased, net	MMBtus	8,320,000	6	3,240,000	3
Natural gas basis swaps purchased	MMBtus	1,780,000	6	1,290,000	12
Natural gas over-the-counter swaps, net (b)	MMBtus	4,525,100	20	4,600,000	24
Natural gas physical contracts, net (c)	MMBtus	23,350,287	13	13,548,235	12
Electric wholesale contracts (c)	MWh	55,225	3	—	0

__________

(a) Term reflects the maximum forward period hedged.

(b) As of September 30, 2020, 1,274,900 MMBtus of natural gas over-the-counter swaps purchases were designated as cash flow hedges.

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value

The following table presents the fair value and balance sheet classification of our derivative instruments (in thousands) as of:


	Balance Sheet Location	September 30, 2020		December 31, 2019
Derivatives designated as hedges:
Asset derivative instruments:
Current commodity derivatives	Derivative assets, current	$	435	$	1
Noncurrent commodity derivatives	Other assets, non-current	94		3
Liability derivative instruments:
Current commodity derivatives	Derivative liabilities, current	(9)		(490)
Noncurrent commodity derivatives	Other deferred credits and other liabilities	—		(29)
Total derivatives designated as hedges		$	520	$	(515)

Derivatives not designated as hedges:
Asset derivative instruments:
Current commodity derivatives	Derivative assets, current	$	1,566	$	341
Noncurrent commodity derivatives	Other assets, non-current	434		2
Liability derivative instruments:
Current commodity derivatives	Derivative liabilities, current	(1,430)		(1,764)
Noncurrent commodity derivatives	Other deferred credits and other liabilities	—		(63)
Total derivatives not designated as hedges		$	570	$	(1,484)

Derivative Instruments, Gain (Loss)


	Three Months Ended September 30,					Three Months Ended September 30,
	2020		2019			2020		2019
Derivatives in Cash Flow Hedging Relationships	Amount of (Gain)/Loss Recognized in OCI				Income Statement Location	Amount of Gain/(Loss) Reclassified from AOCI into Income
	(in thousands)					(in thousands)
Interest rate swaps	$	712	$	713	Interest expense	$	(712)	$	(713)
Commodity derivatives	691		(21)		Fuel, purchased power and cost of natural gas sold	(178)		(129)
Total	$	1,403	$	692		$	(890)	$	(842)


	Nine Months Ended September 30,					Nine Months Ended September 30,
	2020		2019			2020		2019
Derivatives in Cash Flow Hedging Relationships	Amount of (Gain)/Loss Recognized in OCI				Income Statement Location	Amount of Gain/(Loss) Reclassified from AOCI into Income
	(in thousands)					(in thousands)
Interest rate swaps	$	2,138	$	2,139	Interest expense	$	(2,138)	$	(2,139)
Commodity derivatives	959		(942)		Fuel, purchased power and cost of natural gas sold	(734)		508
Total	$	3,097	$	1,197		$	(2,872)	$	(1,631)

Derivatives Not Designated as Hedges



		Three Months Ended September 30,
		2020		2019
Derivatives Not Designated as Hedging Instruments	Income Statement Location	Amount of Gain/(Loss) on Derivatives Recognized in Income

Commodity derivatives - Electric	Fuel, purchased power and cost of natural gas sold	$	(1,386)	$	—
Commodity derivatives - Electric	Other income (expense), net	—		142
Commodity derivatives - Natural Gas	Fuel, purchased power and cost of natural gas sold	1,777		(20)
		$	391	$	122


		Nine Months Ended September 30,
		2020		2019
Derivatives Not Designated as Hedging Instruments	Income Statement Location	Amount of Gain/(Loss) on Derivatives Recognized in Income
		(in thousands)
Commodity derivatives - Electric	Fuel, purchased power and cost of natural gas sold	$	(228)	$	—
Commodity derivatives - Electric	Other income (expense), net	—		142
Commodity derivatives - Natural Gas	Fuel, purchased power and cost of natural gas sold	2,992		(1,180)
		$	2,764	$	(1,038)

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Hierarchy, Measured on Recurring Basis

Recurring Fair Value Measurements

Derivatives


	As of September 30, 2020
	Level 1		Level 2		Level 3		Cash Collateral and Counterparty Netting		Total
	(in thousands)
Assets:
Commodity derivatives — Gas Utilities	$	—	$	6,544	$	—	$	(4,015)	$	2,529
Commodity derivatives — Electric Utilities	—		—		—		—		—
Total	$	—	$	6,544	$	—	$	(4,015)	$	2,529

Liabilities:
Commodity derivatives — Gas Utilities	$	—	$	1,537	$	—	$	(326)	$	1,211
Commodity derivatives — Electric Utilities	—		228		—		—		$	228
Total	$	—	$	1,765	$	—	$	(326)	$	1,439


	As of December 31, 2019
	Level 1		Level 2		Level 3		Cash Collateral and Counterparty Netting		Total
	(in thousands)
Assets:
Commodity derivatives — Gas Utilities	$	—	$	1,433	$	—	$	(1,085)	$	348
Total	$	—	$	1,433	$	—	$	(1,085)	$	348

Liabilities:
Commodity derivatives — Gas Utilities	$	—	$	5,254	$	—	$	(2,909)	$	2,345
Total	$	—	$	5,254	$	—	$	(2,909)	$	2,345

Fair Value, by Balance Sheet Grouping

The following table presents the carrying amounts and fair values of financial instruments not recorded at fair value on the Condensed Consolidated Balance Sheets (in thousands) as of:


	September 30, 2020				December 31, 2019
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term debt, including current maturities (a)	$	3,536,765	$	4,177,801	$	3,145,839	$	3,479,367

__________

Other Comprehensive Income (Loss) (Tables)

9 Months Ended

Sep. 30, 2020

Statement of Comprehensive Income [Abstract]

Reclassification Out of Accumulated Other Comprehensive Income (Loss)


	Location on the Condensed Consolidated Statements of Income	Amount Reclassified from AOCI
		Three Months Ended September 30,				Nine Months Ended September 30,
		2020		2019		2020		2019
Gains and (losses) on cash flow hedges:
Interest rate swaps	Interest expense	$	(712)	$	(713)	$	(2,138)	$	(2,139)
Commodity contracts	Fuel, purchased power and cost of natural gas sold	(178)		(129)		(734)		508
		(890)		(842)		(2,872)		(1,631)
Income tax	Income tax benefit (expense)	209		170		680		358
Total reclassification adjustments related to cash flow hedges, net of tax		$	(681)	$	(672)	$	(2,192)	$	(1,273)

Amortization of components of defined benefit plans:
Prior service cost	Operations and maintenance	$	24	$	19	$	79	$	58

Actuarial gain (loss)	Operations and maintenance	(597)		(83)		(1,791)		(524)
		(573)		(64)		(1,712)		(466)
Income tax	Income tax benefit (expense)	143		89		407		184
Total reclassification adjustments related to defined benefit plans, net of tax		$	(430)	$	25	$	(1,305)	$	(282)
Total reclassifications		$	(1,111)	$	(647)	$	(3,497)	$	(1,555)

Schedule of Accumulated Other Comprehensive Income (Loss)

Balances by classification included within AOCI, net of tax on the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):


	Interest Rate Swaps		Commodity Derivatives		Employee Benefit Plans		Total
As of December 31, 2019	$	(15,122)	$	(456)	$	(15,077)	$	(30,655)
Other comprehensive income (loss)
before reclassifications	—		181		55		236
Amounts reclassified from AOCI	1,630		562		1,305		3,497
As of September 30, 2020	$	(13,492)	$	287	$	(13,717)	$	(26,922)


	Interest Rate Swaps		Commodity Derivatives		Employee Benefit Plans		Total
As of December 31, 2018	$	(17,307)	$	328	$	(9,937)	$	(26,916)
Other comprehensive income (loss)
before reclassifications	—		(334)		—		(334)
Amounts reclassified from AOCI	1,639		(366)		282		1,555
As of September 30, 2019	$	(15,668)	$	(372)	$	(9,655)	$	(25,695)

Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

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


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	1,352	$	1,346	$	4,058	$	4,037
Interest cost	3,356		4,344		10,069		13,031
Expected return on plan assets	(5,647)		(6,100)		(16,943)		(18,300)
Prior service cost (benefit)	—		6		—		19
Net loss (gain)	2,093		941		6,279		2,822
Net periodic benefit cost	$	1,154	$	537	$	3,463	$	1,609

Defined Benefit Postretirement Healthcare Plan

The components of net periodic benefit cost for the Defined Benefit Postretirement Healthcare Plan were as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	514	$	454	$	1,542	$	1,362
Interest cost	412		560		1,237		1,683
Expected return on plan assets	(46)		(57)		(137)		(172)
Prior service cost (benefit)	(136)		(99)		(410)		(298)
Net loss (gain)	5		—		15		—
Net periodic benefit cost	$	749	$	858	$	2,247	$	2,575

Supplemental Non-qualified Defined Benefit and Defined Contribution Plans

The components of net periodic benefit cost for the Supplemental Non-qualified Defined Benefit and Defined Contribution Plans were as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Service cost	$	1,035	$	429	$	1,482	$	2,406
Interest cost	274		324		824		972
Prior service cost (benefit)	1		—		1		1
Net loss (gain)	425		134		1,277		402
Net periodic benefit cost	$	1,735	$	887	$	3,584	$	3,781

Schedule of Defined Benefit Plans Contributions

Contributions made in the first nine months of 2020 and anticipated contributions for 2020 and 2021 are as follows (in thousands):


	Contributions Made		Additional Contributions		Contributions
	Nine Months Ended September 30, 2020		Anticipated for 2020		Anticipated for 2021
Defined Benefit Pension Plan	$	12,700	$	—	$	12,700
Non-pension Defined Benefit Postretirement Healthcare Plans	$	4,006	$	1,335	$	5,227
Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	1,065	$	355	$	1,964

Investments (Tables)

9 Months Ended

Sep. 30, 2020

Investments, All Other Investments [Abstract]

Investments

The following table presents the carrying value of our investments (in thousands) as of:


	September 30, 2020		December 31, 2019
Investment in privately held oil and gas company	$	1,500	$	8,359
Cash surrender value of life insurance contracts	13,467		13,056
Other investments	692		514
Total investments	$	15,659	$	21,929

Management's Statement: Reclassification (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fuel, purchased power and cost of natural gas sold	$ 71,686	$ 73,544	$ 331,194	$ 413,486
Operations and maintenance	122,759	116,583	365,533	365,116
Operating income	$ 82,234	70,551	$ 302,352	284,683
Scenario, Adjustment
Fuel, purchased power and cost of natural gas sold		500		1,800
Operations and maintenance		(500)		(1,800)
Operating income		$ 0		$ 0

Management's Statement: Management Statement (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 2,620,200	$ 2,614,496	$ 2,624,423		$ 2,464,069	$ 2,432,896	$ 2,419,998	$ 2,383,702	$ 2,287,423
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest			$ (207)	$ (200)		$ 3	$ (3)	$ 3,390

- Definition

Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Revenue: Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 344,312	$ 323,745	$ 1,198,714	$ 1,251,461
Total revenues	346,590	325,548	1,210,554	1,257,246
Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,568	6,846	20,062	19,934
Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	337,744	316,899	1,178,652	1,231,527
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	2,278	1,803	11,840	5,785
Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	270,440	258,870	993,219	1,043,058
Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38,057	28,824	112,680	101,256
Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,453	9,915	19,572	29,061
Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,667	5,103	12,014	12,062
Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20,695	21,033	61,229	66,024
Inter-company Revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(39,899)	(28,449)	(117,083)	(82,796)
Total revenues	(39,935)	(37,943)	(117,902)	(111,502)
Inter-company Revenues \| Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(8,100)	(8,146)	(23,855)	(23,315)
Inter-company Revenues \| Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(31,799)	(20,303)	(93,228)	(59,481)
Inter-company Revenues \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	(36)	(9,494)	(819)	(28,706)
Inter-company Revenues \| Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(8,100)	(8,146)	(23,855)	(23,315)
Inter-company Revenues \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(139)	(195)	(416)	(903)
Inter-company Revenues \| Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(24,521)	(14,414)	(72,609)	(40,923)
Inter-company Revenues \| Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1,904)	(1,488)	(6,123)	(5,047)
Inter-company Revenues \| Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(5,235)	(4,206)	(14,080)	(12,608)
Electric Utilities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200,618	191,150	536,107	538,200
Total revenues	200,842	191,384	538,181	540,665
Electric Utilities \| Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Electric Utilities \| Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200,618	191,150	536,107	538,200
Electric Utilities \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	224	234	2,074	2,465
Electric Utilities \| Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	169,505	162,214	459,949	455,409
Electric Utilities \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Electric Utilities \| Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,925	8,210	14,947	23,334
Electric Utilities \| Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,535	6,452	17,940	16,592
Electric Utilities \| Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,653	14,274	43,271	42,865
Gas Utilities
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	142,876	129,933	658,539	706,158
Total revenues	143,929	130,744	665,812	707,293
Gas Utilities \| Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Gas Utilities \| Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	142,876	129,933	658,539	706,158
Gas Utilities \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	1,053	811	7,273	1,135
Gas Utilities \| Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	94,367	89,810	513,208	567,715
Gas Utilities \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38,196	29,019	113,096	102,159
Gas Utilities \| Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Gas Utilities \| Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36	139	197	517
Gas Utilities \| Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,277	10,965	32,038	35,767
Power Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	26,049	16,119	77,234	46,650
Total revenues	26,518	25,811	78,606	75,764
Power Generation \| Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Power Generation \| Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	26,049	16,119	77,234	46,650
Power Generation \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	469	9,692	1,372	29,114
Power Generation \| Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Power Generation \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Power Generation \| Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	26,049	16,119	77,234	46,650
Power Generation \| Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Power Generation \| Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Mining
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,668	14,992	43,917	43,249
Total revenues	15,236	15,552	45,857	45,026
Mining \| Services transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,668	14,992	43,917	43,249
Mining \| Services transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Mining \| Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	568	560	1,940	1,777
Mining \| Retail - Electric , Natural Gas and Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14,668	14,992	43,917	43,249
Mining \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Mining \| Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Mining \| Market - off-system sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Mining \| Transmission/Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 0	$ 0

Business Segment Information: Information Relating to Segment Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information
Revenue from contracts with customers	$ 344,312			$ 323,745			$ 1,198,714	$ 1,251,461
Revenues	346,590			325,548			1,210,554	1,257,246
Operating income	82,234			70,551			302,352	284,683
Interest expense, net	(36,041)			(33,487)			(107,039)	(102,469)
Impairment of investment	0		$ (6,900)	(19,741)			(6,859)	(19,741)
Other income (expense), net	(1,193)			580			(703)	55
Income tax (expense)	(4,651)			(2,508)			(25,484)	(22,078)
Net income	40,349	$ 24,694	$ 97,224	15,395	$ 17,693	$ 107,362	162,267	140,450
Net income attributable to noncontrolling interest	(4,066)			(3,655)			(11,844)	(10,319)
Net income available for common stock	36,283			11,740			150,423	130,131
Inter-company Revenues
Segment Reporting Information
Revenue from contracts with customers	(39,899)			(28,449)			(117,083)	(82,796)
Revenues	(39,935)			(37,943)			(117,902)	(111,502)
Consolidation, Eliminations
Segment Reporting Information
Revenue from contracts with customers	0			0			0	0
Corporate and Other
Segment Reporting Information
Operating income	(239)			(34)			(108)	(439)
Electric Utilities
Segment Reporting Information
Revenue from contracts with customers	200,618			191,150			536,107	538,200
Revenues	200,842			191,384			538,181	540,665
Operating income	52,083			50,653			121,726	125,219
Gas Utilities
Segment Reporting Information
Revenue from contracts with customers	142,876			129,933			658,539	706,158
Revenues	143,929			130,744			665,812	707,293
Operating income	18,147			4,736			139,253	116,607
Power Generation
Segment Reporting Information
Revenue from contracts with customers	26,049			16,119			77,234	46,650
Revenues	26,518			25,811			78,606	75,764
Operating income	8,738			11,822			31,489	33,945
Mining
Segment Reporting Information
Revenue from contracts with customers	14,668			14,992			43,917	43,249
Revenues	15,236			15,552			45,857	45,026
Operating income	3,505			3,374			9,992	9,351
Other Revenues
Segment Reporting Information
Revenues	2,278			1,803			11,840	5,785
Other Revenues \| Inter-company Revenues
Segment Reporting Information
Revenues	(36)			(9,494)			(819)	(28,706)
Other Revenues \| Consolidation, Eliminations
Segment Reporting Information
Revenues	0			0			0	0
Other Revenues \| Electric Utilities
Segment Reporting Information
Revenues	224			234			2,074	2,465
Other Revenues \| Gas Utilities
Segment Reporting Information
Revenues	1,053			811			7,273	1,135
Other Revenues \| Power Generation
Segment Reporting Information
Revenues	469			9,692			1,372	29,114
Other Revenues \| Mining
Segment Reporting Information
Revenues	568			560			1,940	1,777
External Operating Revenue
Segment Reporting Information
Revenue from contracts with customers	344,312			323,745			1,198,714	1,251,461
External Operating Revenue \| Electric Utilities
Segment Reporting Information
Revenue from contracts with customers	194,941			185,811			518,641	521,614
External Operating Revenue \| Gas Utilities
Segment Reporting Information
Revenue from contracts with customers	141,275			129,385			655,386	704,188
External Operating Revenue \| Power Generation
Segment Reporting Information
Revenue from contracts with customers	1,528			1,703			4,625	5,725
External Operating Revenue \| Mining
Segment Reporting Information
Revenue from contracts with customers	6,568			6,846			20,062	19,934
External Operating Revenue \| Other Revenues
Segment Reporting Information
Revenues	2,278			1,803			11,840	5,785
External Operating Revenue \| Other Revenues \| Electric Utilities
Segment Reporting Information
Revenues	224			234			2,074	2,465
External Operating Revenue \| Other Revenues \| Gas Utilities
Segment Reporting Information
Revenues	863			810			7,083	1,134
External Operating Revenue \| Other Revenues \| Power Generation
Segment Reporting Information
Revenues	414			531			1,206	1,401
External Operating Revenue \| Other Revenues \| Mining
Segment Reporting Information
Revenues	777			228			1,477	785
Inter-company Operating Revenue \| Electric Utilities
Segment Reporting Information
Revenue from contracts with customers	5,677			5,339			17,466	16,586
Inter-company Operating Revenue \| Gas Utilities
Segment Reporting Information
Revenue from contracts with customers	1,601			549			3,153	1,971
Inter-company Operating Revenue \| Power Generation
Segment Reporting Information
Revenue from contracts with customers	24,521			14,415			72,609	40,924
Inter-company Operating Revenue \| Mining
Segment Reporting Information
Revenue from contracts with customers	8,100			8,146			23,855	23,315
Inter-company Operating Revenue \| Other Revenues \| Electric Utilities
Segment Reporting Information
Revenues	0			0			0	0
Inter-company Operating Revenue \| Other Revenues \| Gas Utilities
Segment Reporting Information
Revenues	190			0			190	0
Inter-company Operating Revenue \| Other Revenues \| Power Generation
Segment Reporting Information
Revenues	55			9,162			166	27,714
Inter-company Operating Revenue \| Other Revenues \| Mining
Segment Reporting Information
Revenues	$ (209)			$ 332			$ 463	$ 992

Business Segment Information: Segment and Corporate Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 7,829,050	$ 7,558,457
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	108,418	130,245
Electric Utilities
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,040,064	2,900,983
Gas Utilities
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	4,201,325	4,032,339
Power Generation
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	403,491	417,715
Mining
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 75,752	$ 77,175

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SX 210.4-08(g)(1)(ii))
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-Subparagraph (d)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section S99
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

+ Details

Selected Balance Sheet Information: Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Selected Balance Sheet Information [Abstract]
Accounts receivable, trade	$ 108,351	$ 144,747
Unbilled revenue	60,736	113,502
Less: Allowance for doubtful accounts	(8,609)	(2,444)	$ (3,159)	$ (3,209)
Accounts receivable, net	$ 160,478	$ 255,805

Selected Balance Sheet Information: Changes to Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss, Current	$ 8,609	$ 8,609	$ 3,159	$ 2,444	$ 3,209
Additions Charged to Costs and Expenses		8,471	5,637
Recoveries and Other Additions		3,720	2,742
Write-offs and Other Deductions		(6,026)	$ (8,429)
Adjustment Related to COVID-19
Additions Charged to Costs and Expenses	$ 1,700	$ 3,700

Selected Balance Sheet Information: Materials and Supplies (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Selected Balance Sheet Information [Abstract]
Materials and supplies	$ 93,069	$ 82,809
Fuel - Electric Utilities	1,745	2,425
Natural gas in storage	31,544	31,938
Total materials, supplies and fuel	$ 126,358	$ 117,172

Selected Balance Sheet Information: Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Selected Balance Sheet Information [Abstract]
Accrued employee compensation, benefits and withholdings	$ 65,309	$ 62,837
Accrued property taxes	40,624	44,547
Customer deposits and prepayments	59,510	54,728
Accrued interest	46,044	31,868
Other (none of which is individually significant)	32,523	32,787
Total accrued liabilities	$ 244,010	$ 226,767

Regulatory Matters (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Regulatory assets
Regulatory assets	$ 271,236	$ 271,344
Less current regulatory assets	(49,493)	(43,282)
Regulatory assets, non-current	221,743	228,062
Regulatory liabilities
Regulatory liabilities	527,599	536,652
Less current regulatory liabilities	(22,282)	(33,507)
Regulatory liabilities, non-current	505,317	503,145
Deferred energy and gas costs
Regulatory liabilities
Regulatory liabilities	14,443	17,278
Employee benefit plans
Regulatory liabilities
Regulatory liabilities	40,719	43,349
Cost of removal
Regulatory liabilities
Regulatory liabilities	169,426	166,727
Excess deferred income taxes
Regulatory liabilities
Regulatory liabilities	286,055	285,438
Other regulatory liabilities
Regulatory liabilities
Regulatory liabilities	16,956	23,860
Deferred energy and gas costs
Regulatory assets
Regulatory assets	35,878	34,088
Deferred gas cost adjustments
Regulatory assets
Regulatory assets	3,670	1,540
Gas price derivatives
Regulatory assets
Regulatory assets	499	3,328
Deferred taxes on AFUDC
Regulatory assets
Regulatory assets	7,683	7,790
Employee benefit plans
Regulatory assets
Regulatory assets	114,971	115,900
Environmental
Regulatory assets
Regulatory assets	1,417	1,454
Loss on reacquired debt
Regulatory assets
Regulatory assets	23,342	24,777
Renewable energy standard adjustment
Regulatory assets
Regulatory assets	0	1,622
Deferred taxes on flow through accounting
Regulatory assets
Regulatory assets	44,528	41,220
Decommissioning costs
Regulatory assets
Regulatory assets	9,421	10,670
Gas supply contract termination
Regulatory assets
Regulatory assets	4,027	8,485
Other regulatory assets
Regulatory assets
Regulatory assets	$ 25,800	$ 20,470

Regulatory Matters: Rate Review (Details) $ in Thousands						3 Months Ended	9 Months Ended
Regulatory Matters: Rate Review (Details) $ in Thousands	Jan. 01, 2022	Sep. 11, 2020 USD ($) mi	Jun. 01, 2020 USD ($) mi	May 19, 2020 USD ($)	Feb. 01, 2019 USD ($) utility	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Oct. 15, 2020 MW
Public Utilities, General Disclosures [Line Items]
Income Tax Benefit from Relieved TCJA Related Liabilities						$ 3,500	$ 4,000
Federal Energy Regulatory Commission (FERC) \| Black Hills Wyoming and Wyoming Electric \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Number of Megawatts Capacity Purchased \| MW								60
Public Utilities Term of Power Purchase Agreement	11 years
Rate Review Filed with the Regulatory Agency \| Colorado Public Utilities Commission (CPUC) \| Black Hills Energy, Colorado Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments \| mi		7,000
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 13,500			$ 2,500
Public Utilities, Requested Equity Capital Structure, Percentage		50.00%
Public Utilities, Requested Debt Capital Structure, Percentage		50.00%
Public Utilities, Requested Return on Equity, Percentage		9.95%
Public Utilities, Number of Gas Distribution Territories Consolidating \| utility					2
Public Utilities, Approved Rate Increase (Decrease), Amount				$ 600
Public Utilities, Approved Return on Equity, Percentage				9.20%
Rate Review Filed with the Regulatory Agency \| Nebraska Publc Service Commission (NPSC) \| Black Hills Energy, Nebraska Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments \| mi			13,000
Public Utilities, Requested Rate Increase (Decrease), Amount			$ 17,300
Public Utilities, Requested Equity Capital Structure, Percentage			50.00%
Public Utilities, Requested Debt Capital Structure, Percentage			50.00%
Public Utilities, Requested Return on Equity, Percentage			10.00%
Public Utilities, State Statute Allows for Implementation of Interim Rates After Certain Number of Days Following Filing of Rate Review			90 days
System Safety and Integrity Rider Rate Review Filed with the Regulatory Agency \| Colorado Public Utilities Commission (CPUC) \| Black Hills Energy, Colorado Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Term of Rate Recovery		5 years
System Safety and Integrity Rider Rate Review Filed with the Regulatory Agency \| Nebraska Publc Service Commission (NPSC) \| Black Hills Energy, Nebraska Gas
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Term of Rate Recovery			5 years

Earnings Per Share: Earnings Per Share Reconciliation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income available for common stock	$ 36,283	$ 11,740	$ 150,423	$ 130,131
Weighted average shares - basic (in shares)	62,575	60,976	62,310	60,458
Dilutive effect of:
Equity compensation (in shares)	55	128	52	120
Weighted average shares - diluted (in shares)	62,630	61,104	62,362	60,578
Earnings (loss) per share, Basic (usd per share)	$ 0.58	$ 0.19	$ 2.41	$ 2.15
Earnings (loss) per share, Diluted (usd per share)	$ 0.58	$ 0.19	$ 2.41	$ 2.15

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
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-Paragraph 11
-Subparagraph (b)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-URI http://asc.fasb.org/extlink&oid=121326447&loc=d3e1448-109256

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22595-107794

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-URI http://asc.fasb.org/extlink&oid=121326447&loc=d3e1337-109256

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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- Definition

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

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+ Details

Earnings Per Share: Anti-dilutive shares (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares (in shares)	71	2	62	5
Equity compensation - (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares (in shares)	22	2	22	4
Restricted Stock (in shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares (in shares)	49	0	40	1

Notes Payable, Current Maturities and Debt: Schedule of Short-term Debt and Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Short-term Debt [Line Items]
Notes payable	$ 84,320		$ 349,500
Letters of Credit	24,588		30,274
Net (payments) borrowings of short-term debt	(265,180)	$ 109,280
Commercial Paper
Short-term Debt [Line Items]
Notes payable	84,320		349,500
Letters of Credit	0		0
Revolving Credit Facility
Short-term Debt [Line Items]
Notes payable	0		0
Letters of Credit	24,588		$ 30,274
Line of Credit Facility, Current Borrowing Capacity	$ 750,000

Notes Payable, Current Maturities and Debt: Debt Covenants (Details)	Sep. 30, 2020
Line of Credit Facility [Line Items]
Ratio of Indebtedness to Net Capital	0.593
Maximum
Line of Credit Facility [Line Items]
Consolidated Indebtedness to Capitalization Ratio	0.65

Notes Payable, Current Maturities and Debt: Debt Offering (Details) - USD ($) $ in Thousands		9 Months Ended
	Jun. 17, 2020	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Long-term debt - issuances		$ 400,000	$ 400,000
Senior Unsecured Notes Due 2030
Debt Instrument [Line Items]
Long-term debt - issuances	$ 400,000
Debt Instrument, Interest Rate, Stated Percentage	2.50%
Long-term Debt, Term	10 years

Notes Payable, Current Maturities and Debt: Long-Term Debt (Details) $ in Millions	Mar. 24, 2020 USD ($)
Electric Utilities \| South Dakota Electric \| Bonds Due 2024
Extinguishment of Debt, Amount	$ 2.9

Equity: Equity Issuance (Details) - Private Placement $ / shares in Units, shares in Millions, $ in Millions	Feb. 27, 2020 USD ($) $ / shares shares
Sale of Stock, Number of Shares Issued in Transaction \| shares	1.2
Sale of Stock, Price Per Share \| $ / shares	$ 81.77
Sale of Stock, Consideration Received on Transaction	$ 99.0
Payments of Stock Issuance Costs	$ 1.0

Equity: At-the-Market Equity Offering Program (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Aug. 03, 2020
At The Market Equity Offering Program Authorized Aggregate Value		$ 300,000						$ 400,000
Issuance costs	$ 119	$ 79	$ 967	$ 398	$ 492	$ 289
Common Stock
At The Market Equity Offering Program Shares Issued				400,000			1,300,000
At The Market Equity Program Proceeds from Sale of Stock				$ 30,000			$ 99,000
Issuance costs				$ 300			$ 1,000

Risk Management and Derivatives: Credit Risk (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Credit Loss Expense (Reversal)		$ 8,471	$ 5,637
Adjustment Related to COVID-19
Accounts Receivable, Credit Loss Expense (Reversal)	$ 1,700	$ 3,700

Risk Management and Derivatives: Utilities (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) MMBTU mW	Dec. 31, 2019 MMBTU mW
Derivative [Line Items]
Credit Risk Derivative Liabilities, at Fair Value \| $	$ 500
Natural Gas, Distribution \| Cash Flow Hedging
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,274,900
Natural Gas, Distribution \| Natural gas futures purchased
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,930,000	1,450,000
Derivative, Remaining Maturity	6 months	12 months
Natural Gas, Distribution \| Natural gas options purchased, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	8,320,000	3,240,000
Derivative, Remaining Maturity	6 months	3 months
Natural Gas, Distribution \| Natural gas basis swaps purchased
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	1,780,000	1,290,000
Derivative, Remaining Maturity	6 months	12 months
Natural Gas, Distribution \| Natural gas over-the-counter swaps, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	4,525,100	4,600,000
Derivative, Remaining Maturity	20 months	24 months
Natural Gas, Distribution \| Natural gas physical contracts, net
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	23,350,287	13,548,235
Derivative, Remaining Maturity	13 months	12 months
Electricity \| Electric wholesale contracts
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| mW	55,225	0
Derivative, Remaining Maturity	3 months	0 months

Risk Management and Derivatives: Derivatives by Balance Sheet Classification (Details) - Commodity Contracts - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair Value Hedges, Net	$ 520	$ (515)
Designated as Hedging Instrument \| Derivative assets — current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Assets	435	1
Designated as Hedging Instrument \| Other assets, non-current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Assets	94	3
Designated as Hedging Instrument \| Derivative liabilities — current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Liabilities	(9)	(490)
Designated as Hedging Instrument \| Other deferred credits and other liabilities
Derivatives, Fair Value [Line Items]
Fair Value Hedge Liabilities	0	(29)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Fair Value Hedges, Net	570	(1,484)
Not Designated as Hedging Instrument \| Derivative assets — current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Assets	1,566	341
Not Designated as Hedging Instrument \| Other assets, non-current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Assets	434	2
Not Designated as Hedging Instrument \| Derivative liabilities — current
Derivatives, Fair Value [Line Items]
Fair Value Hedge Liabilities	(1,430)	(1,764)
Not Designated as Hedging Instrument \| Other deferred credits and other liabilities
Derivatives, Fair Value [Line Items]
Fair Value Hedge Liabilities	$ 0	$ (63)

Risk Management and Derivatives: Derivatives Designated as Hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (890)	$ (842)	$ (2,872)	$ (1,631)
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1,403	692	3,097	1,197
Natural Gas, Distribution
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			100
Interest rate swaps \| Designated as Hedging Instrument
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	712	713	2,138	2,139
Commodity Contracts \| Designated as Hedging Instrument
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	691	(21)	959	(942)
Interest expense \| Interest rate swaps
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(712)	(713)	(2,138)	(2,139)
Fuel, purchased power and cost of natural gas sold \| Commodity Contracts
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (178)	$ (129)	$ (734)	$ 508

Risk Management and Derivatives: Derivatives Not Designated as Hedge Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Regulatory assets	$ 271,236		$ 271,236		$ 271,344
Gas price derivatives
Derivative [Line Items]
Regulatory assets	499		499		$ 3,328
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	391	$ 122	2,764	$ (1,038)
Not Designated as Hedging Instrument \| Fuel, purchased power and cost of natural gas sold \| Electricity
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,386)	142	(228)	142
Not Designated as Hedging Instrument \| Fuel, purchased power and cost of natural gas sold \| Natural Gas, Distribution
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 1,777	$ (20)	$ 2,992	$ (1,180)

Fair Value Measurements: Schedule of Fair Values (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	$ (4,015)	$ (1,085)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(326)	(2,909)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Total	2,529	348
Derivative Liabilities, Total	1,439	2,345
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Total	0	0
Derivative Liabilities, Total	0	0
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Total	6,544	1,433
Derivative Liabilities, Total	1,765	5,254
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Total	0	0
Derivative Liabilities, Total	0	0
Gas Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	(4,015)	(1,085)
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	(326)	(2,909)
Gas Utilities \| Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	2,529	348
Derivative Liabilities, Fair Value Disclosure	1,211	2,345
Gas Utilities \| Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0	0
Derivative Liabilities, Fair Value Disclosure	0	0
Gas Utilities \| Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	6,544	1,433
Derivative Liabilities, Fair Value Disclosure	1,537	5,254
Gas Utilities \| Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0	0
Derivative Liabilities, Fair Value Disclosure	0	$ 0
Electric Utilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset	0
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset	0
Electric Utilities \| Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0
Derivative Liabilities, Fair Value Disclosure	228
Electric Utilities \| Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0
Derivative Liabilities, Fair Value Disclosure	0
Electric Utilities \| Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0
Derivative Liabilities, Fair Value Disclosure	228
Electric Utilities \| Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Assets, Commodity Derivatives	0
Derivative Liabilities, Fair Value Disclosure	$ 0

Fair Value Measurements: Other Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 4,177,801	$ 3,479,367
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt	$ 3,536,765	$ 3,145,839

Other Comprehensive Income (Loss): Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Condensed Statement of Income Captions [Line Items]
Interest Expense	$ 36,521			$ 34,000			$ 108,067	$ 103,677
Fuel, purchased power and cost of natural gas sold	71,686			73,544			331,194	413,486
Income before Income Taxes	45,000			17,903			187,751	162,528
Income tax benefit (expense)	(4,651)			(2,508)			(25,484)	(22,078)
Net income (loss)	40,349	$ 24,694	$ 97,224	15,395	$ 17,693	$ 107,362	162,267	140,450
Operations and maintenance	122,759			116,583			365,533	365,116
Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Net income (loss)	(1,111)			(647)			(3,497)	(1,555)
Cash Flow Hedging \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Income before Income Taxes	(890)			(842)			(2,872)	(1,631)
Income tax benefit (expense)	209			170			680	358
Net income (loss)	(681)			(672)			(2,192)	(1,273)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Operations and maintenance	24			19			79	58
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Operations and maintenance	(597)			(83)			(1,791)	(524)
Accumulated Defined Benefit Plans Adjustment \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Income before Income Taxes	(573)			(64)			(1,712)	(466)
Income tax benefit (expense)	143			89			407	184
Net income (loss)	(430)			25			(1,305)	(282)
Interest rate swaps \| Cash Flow Hedging \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Interest Expense	(712)			(713)			(2,138)	(2,139)
Commodity Contracts \| Cash Flow Hedging \| Reclassification out of Accumulated Other Comprehensive Income
Condensed Statement of Income Captions [Line Items]
Fuel, purchased power and cost of natural gas sold	$ (178)			$ (129)			$ (734)	$ 508

Other Comprehensive Income (Loss): Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start	$ (30,655)	$ (26,916)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End	(26,922)	(25,695)
Accumulated Defined Benefit Plans Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start	(15,077)	(9,937)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	55	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End	(13,717)	(9,655)
Accumulated Defined Benefit Plans Adjustment \| Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,305	282
Accumulated Other Comprehensive Income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	236	(334)
Accumulated Other Comprehensive Income (loss) \| Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3,497	1,555
Interest Rate Swaps \| Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start	(15,122)	(17,307)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End	(13,492)	(15,668)
Interest Rate Swaps \| Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent \| Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1,630	1,639
Commodity Contracts \| Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start	(456)	328
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	181	(334)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End	287	(372)
Commodity Contracts \| Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent \| Reclassification out of Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 562	$ (366)

Employee Benefit Plans: Change in Accounting Principle (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Other income (expense), net	$ (1,193)	$ 580	$ (703)	$ 55
Income tax (expense)	(4,651)	(2,508)	(25,484)	(22,078)
Net income available for common stock	$ 36,283	$ 11,740	150,423	$ 130,131
Cumulative Effect, Period of Adoption, Adjustment
Defined Benefit Plan Disclosure [Line Items]
Other income (expense), net			600
Income tax (expense)			200
Net income available for common stock			$ 400

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

- Definition

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

+ References

+ Details

Employee Benefit Plans: Funding Status of Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Benefit plan liabilities	$ 144,049		$ 144,049		$ 154,472
Other income (expense), net	(1,193)	$ 580	(703)	$ 55
Pension Plan
Benefit plan liabilities	$ 51,000		$ 51,000		$ 51,000

Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Pension Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 1,352	$ 1,346	$ 4,058	$ 4,037
Interest cost	3,356	4,344	10,069	13,031
Expected return on plan assets	(5,647)	(6,100)	(16,943)	(18,300)
Prior service cost (benefit)	0	6	0	19
Net loss (gain)	2,093	941	6,279	2,822
Net periodic benefit cost	1,154	537	3,463	1,609
Payment for Pension and Other Postretirement Benefits [Abstract]
Contributions by Employer			12,700
Estimated Future Employer Contributions in Current Fiscal Year	0		0
Estimated Future Employer Contributions in Next Fiscal Year	12,700		12,700
Other Postretirement Benefits Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	514	454	1,542	1,362
Interest cost	412	560	1,237	1,683
Expected return on plan assets	(46)	(57)	(137)	(172)
Prior service cost (benefit)	(136)	(99)	(410)	(298)
Net loss (gain)	5	0	15	0
Net periodic benefit cost	749	858	2,247	2,575
Payment for Pension and Other Postretirement Benefits [Abstract]
Contributions by Employer			4,006
Estimated Future Employer Contributions in Current Fiscal Year	1,335		1,335
Estimated Future Employer Contributions in Next Fiscal Year	5,227		5,227
Supplemental Non-qualified Defined Benefit and Defined Contribution Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1,035	429	1,482	2,406
Interest cost	274	324	824	972
Prior service cost (benefit)	1	0	1	1
Net loss (gain)	425	134	1,277	402
Net periodic benefit cost	1,735	$ 887	3,584	$ 3,781
Payment for Pension and Other Postretirement Benefits [Abstract]
Contributions by Employer			1,065
Estimated Future Employer Contributions in Current Fiscal Year	355		355
Estimated Future Employer Contributions in Next Fiscal Year	$ 1,964		$ 1,964

Commitments and Contingencies: Future Purchase Agreement - Related Party (Details) - MW	Sep. 11, 2020	Jul. 01, 2020	Jun. 26, 2019
Platte River Power Authority Wind Power Agreement
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Megawatts Capacity Purchased			60
Colorado Electric \| City of Colorado Springs
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Megawatts Capacity Purchased		60
South Dakota Electric \| Fall River Solar
Unrecorded Unconditional Purchase Obligation [Line Items]
Number of Megawatts Capacity Purchased	80
Purchase Power Agreement Set to Expire after a Certain Number of Years Following Completion of the Facility	20 years

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax benefit (expense)	$ (4,651)	$ (2,508)	$ (25,484)	$ (22,078)
Effective Tax Rate	10.30%	14.00%	13.60%	13.60%
Amount of Payroll Tax (Social Security Employment Tax) Deferral Allowed Under the CARES Act	$ 4,000		$ 6,900
Proceeds from Income Tax Refunds			$ 2,400

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Investments (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Feb. 28, 2018
Assets used to Acquire Other Investments							$ 28,000
Impairment of investment	$ 0	$ 6,900	$ 19,741	$ 6,859	$ 19,741
Investments	15,659			15,659		$ 21,929
Investment in privately held oil and gas company
Investments	1,500			1,500		8,359
Cash surrender value of life insurance contracts
Investments	13,467			13,467		13,056
Other investments
Investments	$ 692			$ 692		$ 514
Valuation, Income Approach
Discount Rate Used in Valuation of Fair Value of Oil and Gas Reserve Quantities			10.00%		10.00%