Black Hills (BKH) 10-Q 4 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document Information [Line Items]	'	'
Entity Registrant Name	'BLACK HILLS CORP /SD/	'
Entity Central Index Key	'0001130464	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	44,655,369
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'

Condensed_Statements_of_Income

Condensed Statements of Income (unaudited) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue	$272,087	$259,907	$1,015,493	$920,404
Utilities -	'	'	'	'
Fuel, purchased power and cost of natural gas sold	84,674	71,503	416,473	338,848
Operations and maintenance	64,245	66,061	201,546	196,728
Non-regulated energy operations and maintenance	20,170	20,484	63,852	62,703
Depreciation, depletion and amortization	37,463	36,135	110,258	106,068
Taxes - property, production and severance	11,082	10,068	32,462	30,517
Other operating expenses	49	90	323	1,091
Total operating expenses	217,683	204,341	824,914	735,955
Operating income	54,404	55,566	190,579	184,449
Interest charges -	'	'	'	'
Interest expense incurred (including amortization of debt issuance costs, premiums and discounts and realized settlements on interest rate swaps)	-17,919	-23,840	-53,665	-70,881
Allowance for funds used during construction - borrowed	319	347	845	831
Capitalized interest	231	273	734	811
Unrealized gain (loss) on interest rate swaps, net	0	3,144	0	29,393
Interest income	575	565	1,541	1,325
Allowance for funds used during construction - equity	297	85	828	327
Other income (expense), net	261	318	1,262	1,197
Total other income (expense), net	-16,236	-19,108	-48,455	-36,997
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	38,168	36,458	142,124	147,452
Equity in earnings (loss) of unconsolidated subsidiaries	0	0	-1	-86
Income tax benefit (expense)	-11,332	-13,334	-47,349	-50,527
Net income (loss) available for common stock	$26,836	$23,124	$94,774	$96,839
Earnings (loss) per share, Basic -	'	'	'	'
Total income (loss) per share, Basic	$0.60	$0.52	$2.14	$2.19
Earnings (loss) per share, Diluted -	'	'	'	'
Total income (loss) per share, Diluted	$0.60	$0.52	$2.13	$2.18
Weighted Average Number of Shares Outstanding:	'	'	'	'
Basic	44,415	44,201	44,382	44,143
Diluted	44,608	44,457	44,584	44,395
Dividends declared per share of common stock	$0.39	$0.38	$1.17	$1.14

Condensed_Consolidated_Stateme

Condensed Consolidated Statement of Comprehensive Income (unaudited) Statement (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net income (loss) available for common stock	$26,836	$23,124	$94,774	$96,839
Other comprehensive income (loss), net of tax:	'	'	'	'
Fair value adjustments on derivatives designated as cash flow hedges (net of tax (expense) benefit of $(1,840) and $964 for the three months ended 2014 and 2013 and $582 and $(93) for the nine months ended 2014 and 2013, respectively)	3,145	-2,083	-1,071	134
Reclassification adjustments for cash flow hedges settled and included in net income (loss) (net of tax (expense) benefit of $(732) and $(586) for the three months ended 2014 and 2013 and $(1,931) and $(1,469) for the nine months ended 2014 and 2013, respectively)	1,328	1,426	3,511	3,095
Benefit plan liability adjustments - net gain (loss) (net of tax of $0 and $0 for the three months ended 2014 and 2013 and $2 and $0 for the nine months ended 2014 and 2013, respectively)	0	0	-2	0
Benefit plan liability tax adjustments - net gain (loss)	0	0	-394	0
Benefit plan liability adjustments - prior service cost (net of tax of $0 and $0 for the three months ended 2014 and 2013 and $(90) and $0 for the nine months ended 2014 and 2013, respectively)	0	0	164	0
Reclassification adjustments of benefit plan liability - prior service cost (net of tax of $17 and $22 for the three months ended 2014 and 2013 and $60 and $66 for the nine months ended 2014 and 2013, respectively)	-31	-41	-110	-123
Reclassification adjustments of benefit plan liability - net gain (loss) (net of tax of $(86) and $(242) for the three months ended 2014 and 2013 and $(262) and $(729) for the nine months ended 2014 and 2013, respectively)	160	458	485	1,361
Other comprehensive income (loss), net of tax	4,602	-240	2,583	4,467
Comprehensive income (loss) available for common stock	31,438	22,884	97,357	101,306
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures	'	'	'	'
Fair value adjustment on derivatives designated as cash flow hedges, (tax) benefit	-1,840	964	582	-93
Reclassification adjustments of cash flow hedges settled and included in net income, (tax) benefit	-732	-586	-1,931	-1,469
Benefit plan liability adjustments net gain, (tax) benefit	0	0	2	0
Benefit plan liability adjustments prior service cost, (tax) benefit	0	0	-90	0
Reclassification adjustment of benefit plan prior service cost included in net income, (tax) benefit	17	22	60	66
Reclassification adjustment of benefit plan liabilities actuarial gain (loss), (tax) benefit	($86)	($242)	($262)	($729)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (unaudited) Statement (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Current assets:	'	'	'
Cash and cash equivalents	$11,939	$7,841	$13,637
Restricted cash and equivalents	1,918	2	6,782
Accounts receivable, net	123,399	177,573	114,137
Materials, supplies and fuel	105,726	88,478	95,230
Derivative assets, current	0	717	126
Income tax receivable, net	1,268	1,460	4,539
Deferred income tax assets, net, current	34,756	18,889	37,163
Regulatory assets, current	68,444	24,451	30,208
Other current assets	26,502	25,877	27,075
Total current assets	373,952	345,288	328,897
Investments	17,144	16,697	16,612
Property, plant and equipment	4,493,696	4,259,445	4,152,097
Less accumulated depreciation and depletion	-1,338,509	-1,269,148	-1,258,450
Total property, plant and equipment, net	3,155,187	2,990,297	2,893,647
Other assets:	'	'	'
Goodwill	353,396	353,396	353,396
Intangible assets, net	3,231	3,397	3,453
Regulatory assets, non-current	140,422	138,197	183,119
Derivative assets, non-current	0	0	0
Other assets, non-current	29,930	27,906	22,116
Total other assets, non-current	526,979	522,896	562,084
TOTAL ASSETS	4,073,262	3,875,178	3,801,240
Current liabilities:	'	'	'
Accounts payable	100,444	130,416	77,077
Accrued liabilities	163,374	151,277	152,911
Derivative liabilities, current	3,397	3,474	65,944
Regulatory liabilities, current	828	10,727	14,707
Notes payable	184,000	82,500	138,300
Current maturities of long-term debt	275,000	0	255,694
Total current liabilities	727,043	378,394	704,633
Long-term debt, net of current maturities	1,107,519	1,396,948	955,979
Deferred credits and other liabilities:	'	'	'
Deferred income tax liabilities, net, non-current	506,166	432,287	403,772
Derivative liabilities, non-current	3,273	5,614	11,388
Regulatory liabilities, non-current	118,856	109,429	131,730
Benefit plan liabilities	108,924	111,479	169,448
Other deferred credits and other liabilities	144,089	133,279	133,341
Total deferred credits and other liabilities	881,308	792,088	849,679
Commitments and contingencies (See Notes 7, 8, 13, 14 and 15)	'	'	'
Stockholders’ equity:	'	'	'
Common stock $1 par value; 100,000,000 shares authorized; issued 44,696,670; 44,550,239; and 44,532,245 shares, respectively	44,697	44,550	44,532
Additional paid-in capital	746,575	742,344	740,209
Retained earnings	582,800	540,244	539,030
Treasury stock, at cost – 41,552; 50,877; and 41,127 shares, respectively	-1,841	-1,968	-1,801
Accumulated other comprehensive income (loss)	-14,839	-17,422	-31,021
Total stockholders’ equity	1,357,392	1,307,748	1,290,949
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$4,073,262	$3,875,178	$3,801,240

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (unaudited) Parantheticals (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Common Stock, Par Per Share	$1	$1	$1
Common Stock, Shares Issued	44,696,670	44,550,239	44,532,245
Treasury Stock, Shares	41,552	50,877	47,127
Common Stock, Shares Authorized	100,000,000	100,000,000	100,000,000
Common Stock, Shares Outstanding	44,655,118	44,499,362	44,485,118

Condensed_Consoldiated_Stateme

Condensed Consoldiated Statement of Cash Flows (unaudited) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating activities:	'	'
Net income (loss) available for common stock	$94,774	$96,839
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	110,258	106,068
Deferred financing cost amortization	1,608	3,209
Derivative fair value adjustments	2,136	275
Stock compensation	6,978	9,100
Unrealized (gain) loss on interest rate swaps, net	0	-29,393
Deferred income taxes	48,007	54,865
Employee benefit plans	11,109	16,644
Other adjustments, net	2,016	9,434
Changes in certain operating assets and liabilities:	'	'
Materials, supplies and fuel	-17,248	-12,522
Accounts receivable, unbilled revenue and other operating assets	-61	28,762
Accounts payable and other current liabilities	-14,307	-23,774
Contributions to defined benefit pension plans	-10,200	-12,500
Other operating activities, net	4,087	4,759
Net cash provided by (used in) operating activities	239,157	251,766
Investing activities:	'	'
Property, plant and equipment additions	-290,299	-239,485
Proceeds from sale of assets	22,342	0
Other investing activities	-2,364	2,846
Net cash provided by (used in) investing activities	-270,321	-236,639
Financing activities:	'	'
Dividends paid on common stock	-52,218	-50,678
Common stock issued	2,393	3,606
Short-term borrowings - issuances	396,250	269,600
Short-term borrowings - repayments	-294,750	-408,300
Long-term debt - issuances	0	275,000
Long-term debt - repayments	-12,200	-106,180
Other financing activities	-4,213	0
Net cash provided by (used in) financing activities	35,262	-16,952
Net change in cash and cash equivalents	4,098	-1,825
Cash and Cash Equivalents:	'	'
Cash and cash equivalents, beginning of period	7,841	15,462
Cash and cash equivalents, end of period	$11,939	$13,637

Managements_Statement

Management's Statement	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Management's Statement [Text Block]	'
	MANAGEMENT’S STATEMENT
	The unaudited Condensed Consolidated Financial Statements included herein have been prepared by Black Hills Corporation (together with our subsidiaries the “Company,” “us,” “we,” or “our”), pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to such rules and regulations; however, we believe that the footnotes adequately disclose the information presented. These Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our 2013 Annual Report on Form 10-K filed with the SEC.
	We conduct our operations through the following reportable segments: Electric Utilities, Gas Utilities, Power Generation, Coal Mining and Oil and Gas. Our reportable segments are based on our method of internal reporting, which generally segregates the strategic business groups due to differences in products, services and regulation. All of our operations and assets are located within the United States.
	Accounting methods historically employed require certain estimates as of interim dates. The information furnished in the accompanying Condensed Consolidated Financial Statements reflects all adjustments, including accruals, which are, in the opinion of management, necessary for a fair presentation of the September 30, 2014, December 31, 2013, and September 30, 2013 financial information and are of a normal recurring nature. Certain industries in which we operate are highly seasonal, and revenue from, and certain expenses for, such operations may fluctuate significantly among quarterly periods. Demand for electricity and natural gas is sensitive to seasonal cooling, heating and industrial load requirements, as well as changes in market price. In particular, the normal peak usage season for 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, 2014 and September 30, 2013, and our financial condition as of September 30, 2014, December 31, 2013, and September 30, 2013, are not necessarily indicative of the results of operations and financial condition to be expected as of or for any other period. All earnings per share amounts discussed refer to diluted earnings per share unless otherwise noted.
	Recently Issued and Adopted Accounting Standards
	We have implemented all new accounting pronouncements that are in effect and may impact our financial statements and do not believe that there are any other new accounting pronouncements that have been issued that might have a material impact on our financial position, results of operations, or cash flows.
	Revenue from Contracts with Customers, ASU 2014-09
	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers. The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. ASU 2014-09 is effective for annual and interim reporting periods beginning after December 15, 2016 and early adoption is not permitted. We are currently assessing the impact, if any, that ASU 2014-09 will have on our financial position, results of operations or cash flows.

Business_Segment_Information

Business Segment Information	9 Months Ended
	Sep. 30, 2014
Segment Reporting Information, Additional Information [Abstract]	'
Business Segment Information [Text Block]	'
	BUSINESS SEGMENT INFORMATION
	Segment information and Corporate activities included in the accompanying Condensed Consolidated Statements of Income (Loss) were as follows (in thousands):
	Three Months Ended September 30, 2014		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	171,395		$	3,156			$	18,154
	Gas		78,735			—				1,597
	Non-regulated Energy:
	Power Generation		1,602			20,419				7,829
	Coal Mining		6,884			8,689				2,638
	Oil and Gas		13,471			—				(3,110		)
	Corporate activities		—			—				(272		)
	Inter-company eliminations		—			(32,264		)		—
	Total		$	272,087		$	—			$	26,836
	Three Months Ended September 30, 2013		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	169,401		$	2,003			$	15,097
	Gas		67,792			—				(1,450		)
	Non-regulated Energy:
	Power Generation		1,575			20,393				6,707
	Coal Mining		6,713			8,604				2,142
	Oil and Gas		14,426			—				(1,682		)
	Corporate activities (a)		—			—				2,310
	Inter-company eliminations		—			(31,000		)		—
	Total		$	259,907		$	—			$	23,124
	Nine Months Ended September 30, 2014		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	508,230		$	10,307			$	44,156
	Gas		440,571			—				28,289
	Non-regulated Energy:
	Power Generation		4,138			62,211				23,096
	Coal Mining		19,085			26,637				7,118
	Oil and Gas		43,469			—				(6,792		)
	Corporate activities		—			—				(1,093		)
	Inter-company eliminations		—			(99,155		)		—
	Total		$	1,015,493		$	—			$	94,774
	Nine Months Ended September 30, 2013		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	482,222		$	9,844			$	38,063
	Gas		373,440			—				20,225
	Non-regulated Energy:
	Power Generation		3,628			58,825				17,382
	Coal Mining		19,530			23,688				5,180
	Oil and Gas		41,584			—				(3,699		)
	Corporate activities (a)		—			—				19,688
	Inter-company eliminations		—			(92,357		)		—
	Total		$	920,404		$	—			$	96,839
	__________
	(a)	Corporate activities include a $2.0 million and a $19 million after-tax non-cash mark-to-market gain on certain interest rate swaps for the three and nine months ended September 30, 2013, respectively.
	Segment information and Corporate balances included in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):
	Total Assets (net of inter-company eliminations) as of:	30-Sep-14			31-Dec-13				30-Sep-13
	Utilities:
	Electric (a)	$	2,671,601		$	2,525,947			$	2,464,123
	Gas	827,069			805,617				757,746
	Non-regulated Energy:
	Power Generation (a)	64,359			95,692				102,331
Coal Mining	74,130			78,825				82,155
Oil and Gas	330,781			288,366				264,785
Corporate activities	105,322			80,731				130,100
Total assets	$	4,073,262		$	3,875,178			$	3,801,240
__________
(a)	The PPA under which Black Hills Colorado IPP provides generation to support Colorado Electric customers from the Pueblo Airport Generation Station is accounted for as a capital lease. As such, assets owned by our Power Generation segment are recorded at Colorado Electric under accounting for a capital lease.

Accounts_Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Accounts Receivable [Text Block]	'
	ACCOUNTS RECEIVABLE
	Following is a summary of Accounts receivable, net included in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:
		Accounts		Unbilled		Less Allowance for			Accounts
	30-Sep-14	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	53,717	$	21,485	$	(724	)	$	74,478
	Gas Utilities	23,409		13,218		(740		)	35,887
	Power Generation	1,368		—		—			1,368
	Coal Mining	2,563		—		—			2,563
	Oil and Gas	7,657		—		(13		)	7,644
	Corporate	1,459		—		—			1,459
	Total	$	90,173	$	34,703	$	(1,477	)	$	123,399
		Accounts		Unbilled		Less Allowance for			Accounts
	31-Dec-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	52,437	$	23,823	$	(666	)	$	75,594
	Gas Utilities	49,162		41,195		(558		)	89,799
	Power Generation	1,722		—		—			1,722
	Coal Mining	1,711		—		—			1,711
	Oil and Gas	8,156		—		(13		)	8,143
	Corporate	604		—		—			604
	Total	$	113,792	$	65,018	$	(1,237	)	$	177,573
		Accounts		Unbilled		Less Allowance for			Accounts
	30-Sep-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	49,254	$	20,153	$	(648	)	$	68,759
	Gas Utilities	20,693		11,877		(542		)	32,028
	Power Generation	3		—		—			3
	Coal Mining	2,677		—		—			2,677
	Oil and Gas	8,463		—		(19		)	8,444
	Corporate	2,226		—		—			2,226
	Total	$	83,316	$	32,030	$	(1,209	)	$	114,137

Regulatory_Accounting

Regulatory Accounting	9 Months Ended
	Sep. 30, 2014
Regulatory Assets and Liabilities Disclosure [Abstract]	'
Regulatory Accounting [Text Block]	'
	REGULATORY ACCOUNTING
	We had the following regulatory assets and liabilities (in thousands):
		Maximum	As of		As of		As of
		Amortization (in years)	30-Sep-14		31-Dec-13		30-Sep-13
	Regulatory assets
	Deferred energy and fuel cost adjustments - current (a)(d)	1	$	26,211	$	16,775	$	17,925
	Deferred gas cost adjustments and natural gas price derivatives (a)(d)	7	49,870		12,366		16,845
	AFUDC (b)	45	12,411		12,315		12,398
	Employee benefit plans (c)	13	64,908		67,059		114,386
	Environmental (a)	subject to approval	1,314		1,800		1,800
	Asset retirement obligations (a)	44	3,282		3,266		3,262
	Bond issue cost (a)	24	3,311		3,419		3,454
	Renewable energy standard adjustment (a)	5	12,007		14,186		14,936
	Flow through accounting (c)	35	25,157		20,916		19,222
	Other regulatory assets (a)	15	10,395		10,546		9,099
			$	208,866	$	162,648	$	213,327
	Regulatory liabilities
	Deferred energy and gas costs (a)	1	$	5,535	$	11,708	$	14,032
	Employee benefit plans (c)	13	34,409		34,431		60,707
	Cost of removal (a)	44	71,362		64,970		62,069
	Other regulatory liabilities (c)	25	8,378		9,047		9,629
			$	119,684	$	120,156	$	146,437
	__________
	(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, respectively.
	(d)	Our deferred energy, fuel cost, and gas cost adjustments represent the cost of electricity and gas delivered to our electric and gas utility customers that is either higher or lower than current rates and will be recovered or refunded in future rates. Increases in the current year balances as of September 30, 2014 are primarily due to higher natural gas prices driven by demand and market conditions during our peak winter heating season. Our electric and gas utilities file periodic quarterly, semi-annual, and/or annual filings to recover these costs based on the respective cost mechanisms approved by their applicable state utility commissions.

Materials_Supplies_and_Fuel

Materials, Supplies and Fuel	9 Months Ended
	Sep. 30, 2014
Inventory, Net [Abstract]	'
Materials, Supplies and Fuel [Text Block]	'
	MATERIALS, SUPPLIES AND FUEL
	The following amounts by major classification are included in Materials, supplies and fuel in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:
		30-Sep-14		31-Dec-13		30-Sep-13
	Materials and supplies	$	52,682	$	50,196	$	50,564
	Fuel - Electric Utilities	7,108		6,213		6,384
	Natural gas in storage held for distribution	45,936		32,069		38,282
	Total materials, supplies and fuel	$	105,726	$	88,478	$	95,230

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share [Text Block]	'
	EARNINGS PER SHARE
	A reconciliation of share amounts used to compute Earnings (loss) per share in the accompanying Condensed Consolidated Statements of Income (loss) is as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014		2013
	Net income (loss) available for common stock	$	26,836		$	23,124		$	94,774	$	96,839
	Weighted average shares - basic	44,415			44,201			44,382		44,143
	Dilutive effect of:
	Equity compensation	193			256			202		252
	Weighted average shares - diluted	44,608			44,457			44,584		44,395
	The following outstanding securities were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive (in thousands):
		Three Months Ended September 30,					Nine Months Ended September 30,
		2014		2013			2014	2013
	Equity compensation	99		—			75	9
	Anti-dilutive shares	99		—			75	9

Notes_Payable_and_Current_Matu

Notes Payable and Current Maturities of Long-term Debt

9 Months Ended

Sep. 30, 2014

Debt Disclosure [Abstract]

'

Notes Payable [Text Block]

'

NOTES PAYABLE AND CURRENT MATURITIES OF LONG-TERM DEBT

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

30-Sep-14

31-Dec-13

30-Sep-13

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Revolving Credit Facility

$

184,000

$

31,726

$

82,500

$

22,100

$

138,300

$

53,137

Revolving Credit Facility

On May 29, 2014, we amended our $500 million corporate Revolving Credit Facility agreement to extend the term through May 29, 2019. This facility is substantially similar to the former agreement, which includes an accordion feature that allows us, with the consent of the administrative agent and issuing agents, to increase the capacity of the facility to $750 million. Borrowings continue to be available under a base rate or various Eurodollar rate options. The interest costs associated with the letters of credit or borrowings and the commitment fee under the Revolving Credit Facility are determined based upon our most favorable Corporate credit rating from S&P and Moody’s for our unsecured debt. Based on our credit ratings, the margins for base rate borrowings, Eurodollar borrowings, and letters of credit were 0.125%, 1.125%, and 1.125%, respectively, from May 29, 2014 through September 30, 2014; a reduction of 0.25% for each method of borrowing as compared to the previous arrangement. Borrowings under the facility are primarily Eurodollar based. A commitment fee is charged on the unused amount of the Revolving Credit Facility and was 0.175% based on our credit rating, a reduction of 0.025% compared to the prior arrangement.

Current Maturities of Long-Term Debt

As of September 30, 2014, our $275 million Corporate term loan due June 19, 2015 is classified as Current maturities of long-term debt.

Debt Covenants

Our Revolving Credit Facility and our Term Loan require compliance with the following financial covenant at the end of each quarter:

As of September 30, 2014

Covenant Requirement

Recourse Leverage Ratio

54%

Less than

65%

As of September 30, 2014, we were in compliance with this covenant.

Risk_Management_Activities_Not

Risk Management Activities (Notes)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Risk Management Activities	'
	RISK MANAGEMENT ACTIVITIES
	Our activities in the regulated and non-regulated energy sectors expose us to a number of risks in the normal operation of our businesses. Depending on the activity, we are exposed to varying degrees of market risk and credit risk. To manage and mitigate these identified risks, we have adopted the Black Hills Corporation Risk Policies and Procedures as discussed in our 2013 Annual Report on Form 10-K.
	Market Risk
	Market risk is the potential loss that might occur as a result of an adverse change in market price or rate. We are exposed to the following market risks including, but not limited to:
	•	Commodity price risk associated with our natural long position in crude oil and natural gas reserves and production; and our fuel procurement for certain of our gas-fired generation assets; and
	•	Interest rate risk associated with our variable-rate debt.
	Credit Risk
	Credit risk is the risk of financial loss resulting from non-performance of contractual obligations by a counterparty.
	For production and generation activities, we attempt to mitigate our credit exposure by conducting business primarily with 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, prepayments, letters of credit, and other security agreements.
	We perform ongoing credit evaluations of our customers and adjust credit limits based upon payment history and the customer’s current creditworthiness, as determined by review of their current credit information. We maintain a provision for estimated credit losses based upon historical experience and any specific customer collection issue that is identified.
	As of September 30, 2014, our credit exposure included a $0.5 million exposure to non-investment grade energy marketing companies. The remainder of our credit exposure was concentrated primarily among retail utility customers, investment grade rated companies, cooperative utilities and federal agencies. Our derivative and hedging activities recorded in the accompanying Condensed Consolidated Balance Sheets, Condensed Consolidated Statements of Income (Loss) and Condensed Consolidated Statements of Comprehensive Income (Loss) are detailed below and in Note 9.
	Oil and Gas
	We produce natural gas and crude oil through our exploration and production activities. Our natural long positions, or unhedged open positions, result in commodity price risk and variability to our cash flows.
	To mitigate commodity price risk and preserve cash flows, we primarily use OTC swaps, exchange traded futures and related options to hedge portions of our crude oil and natural gas production. We elect hedge accounting on these instruments. These transactions were designated at inception as cash flow hedges, documented under accounting standards for derivatives and hedging, and initially met prospective effectiveness testing. Effectiveness of our hedging position is evaluated at least quarterly.
	The derivatives were marked to fair value and were recorded as Derivative assets or Derivative liabilities on the accompanying Condensed Consolidated Balance Sheets. The effective portion of the gain or loss on these derivatives for which we have elected cash flow hedge accounting is reported in AOCI in the accompanying Condensed Consolidated Balance Sheets and the ineffective portion, if any, is reported in Revenue in the accompanying Condensed Consolidated Statements of Income (Loss).
	The contract or notional amounts, terms of our commodity derivatives, and the derivative balances for our Oil and Gas segment reflected on the Condensed Consolidated Balance Sheets were as follows (dollars in thousands) as of:
		30-Sep-14							31-Dec-13							30-Sep-13
		Crude Oil Futures, Swaps and Options			Natural Gas Futures and Swaps				Crude Oil Futures, Swaps and Options			Natural Gas Futures and Swaps				Crude Oil Futures, Swaps and Options		Natural Gas Futures and Swaps
	Notional (a)	391,500			7,930,000				412,500			7,082,500				499,500		9,874,000
	Maximum terms in months (b)	1			1				3			1				3		1
	Derivative assets, current	$	—		$	—			$	55		$	—			$	13	$	113
	Derivative assets, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	Derivative liabilities, current	$	—		$	—			$	—		$	—			$	98	$	52
	Derivative liabilities, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	__________
	(a)	Crude oil in Bbls, natural gas in MMBtus.
	(b)	Refers to the tenor of the derivative instrument. Assets and liabilities are classified as current/non-current based on the production month hedged and the corresponding settlement of the derivative instrument.
	A $0.7 million gain is included in AOCI at September 30, 2014, and would be realized over the next 12 months if market prices remained equal to September 30, 2014 prices. Future realized gains or losses fluctuate with market prices.
	Utilities
	The operations of our utilities, including natural gas sold by our Gas Utilities and natural gas used for Electric Utility generation plants or those plants under PPAs where our Electric Utilities must provide the generation fuel (tolling agreements), 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 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. 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 state commission guidelines. When the related costs are recovered through our rates, the hedging activity is recognized in the Condensed Consolidated Statements of Income (Loss).
	The contract or notional amounts and terms of the natural gas derivative commodity instruments held at our Utilities were as follows, as of:
		30-Sep-14					31-Dec-13					30-Sep-13
		Notional			Maximum		Notional			Maximum		Notional			Maximum
		(MMBtus)			Term		(MMBtus)			Term		(MMBtus)			Term
					(months) (a)					(months) (a)					(months) (a)
	Natural gas futures purchased	16,290,000			74		17,930,000			84		14,010,000			74
	Natural gas options purchased	7,070,000			6		3,890,000			8		6,810,000			6
	Natural gas basis swaps purchased	12,025,000			63		14,785,000			60		9,790,000			63
	__________
	(a) Term reflects the maximum forward period hedged.
	We had the following derivative balances related to the hedges in our Utilities reflected in our Condensed Consolidated Balance Sheets as of (in thousands):
		30-Sep-14			31-Dec-13			30-Sep-13
	Derivative assets, current	$	—		$	662		$	—
	Derivative assets, non-current	$	—		$	—		$	—
	Derivative liabilities, non-current	$	—		$	—		$	—
	Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	7,470		$	7,567		$	10,652
	Financing Activities
	We entered into floating-to-fixed interest rate swap agreements to reduce our exposure to interest rate fluctuations associated with our floating rate debt obligations. The contract or notional amounts, terms of our interest rate swaps and the interest rate swaps balances reflected on the Condensed Consolidated Balance Sheets were as follows (dollars in thousands) as of:
		30-Sep-14				31-Dec-13				30-Sep-13
		Interest Rate				Interest Rate				Interest Rate			De-designated
		Swaps (a)				Swaps (a)				Swaps (b)			Interest Rate
													Swaps (c)
	Notional	$	75,000			$	75,000			$	150,000		$	250,000
	Weighted average fixed interest rate	4.97		%		4.97		%		5.04		%	5.67		%
	Maximum terms in years	2.25				3				3.25			0.25
	Derivative liabilities, current	$	3,397			$	3,474			$	7,039		$	58,755
	Derivative liabilities, non-current	$	3,273			$	5,614			$	11,388		$	—
	__________
	(a)	These swaps are designated to borrowings on our Revolving Credit Facility, and are priced using three-month LIBOR, matching the floating portion of the related debt.
	(b)	At September 30, 2013, $75 million of these interest rate swaps was designated to borrowings on our Revolving Credit Facility and $75 million was designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps were priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that was designated to Black Hills Wyoming was settled during the fourth quarter of 2013 upon repayment of the Black Hills Wyoming project financing.
	(c)	These swaps were settled during the fourth quarter of 2013.
	Based on September 30, 2014, market interest rates and balances related to our interest rate swaps, a loss of approximately $3.4 million would be realized, reported in pre-tax earnings and reclassified from AOCI during the next 12 months. Estimated and actual realized gains or losses will change during future periods as market interest rates change.
	Cash Flow Hedges
The impacts of cash flow hedges on our Condensed Consolidated Statements of Income (Loss) were as follows (in thousands):
Three Months Ended September 30, 2014
Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
		Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
		Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
		in AOCI				from AOCI		from AOCI				in Income		Income on
		Derivative				into Income		into Income				on Derivative		Derivative
		(Effective				(Effective		(Effective				(Ineffective		(Ineffective
		Portion)				Portion)		Portion)				Portion)		Portion)
Interest rate swaps		$	152			Interest expense		$	(925	)				$	—
Commodity derivatives		4,833				Revenue		(1,135		)				—
Total		$	4,985					$	(2,060	)				$	—
Three Months Ended September 30, 2013
Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
		Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
		Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
		in AOCI				from AOCI		from AOCI				in Income		Income on
		Derivative				into Income		into Income				on Derivative		Derivative
		(Effective				(Effective		(Effective				(Ineffective		(Ineffective
		Portion)				Portion)		Portion)				Portion)		Portion)
Interest rate swaps		$	(907	)		Interest expense		$	(1,844	)				$	—
Commodity derivatives		(2,140		)		Revenue		(168		)				—
Total		$	(3,047	)				$	(2,012	)				$	—
Nine Months Ended September 30, 2014
Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
		Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
		Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
		in AOCI				from AOCI		from AOCI				in Income		Income on
		Derivative				into Income		into Income				on Derivative		Derivative
		(Effective				(Effective		(Effective				(Ineffective		(Ineffective
		Portion)				Portion)		Portion)				Portion)		Portion)
Interest rate swaps		$	(277	)		Interest expense		$	(2,745	)				$	—
Commodity derivatives		(1,376		)		Revenue		(2,697		)				—
Total		$	(1,653	)				$	(5,442	)				$	—
Nine Months Ended September 30, 2013
Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
		Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
		Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
		in AOCI				from AOCI		from AOCI				in Income		Income on
		Derivative				into Income		into Income				on Derivative		Derivative
		(Effective				(Effective		(Effective				(Ineffective		(Ineffective
		Portion)				Portion)		Portion)				Portion)		Portion)
Interest rate swaps		$	141			Interest expense		$	(5,460	)				$	—
Commodity derivatives		86				Revenue		896						—
Total		$	227					$	(4,564	)				$	—

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements [Text Block]	'
	FAIR VALUE MEASUREMENTS
	Derivative Financial Instruments
	The accounting guidance for fair value measurements requires certain disclosures about assets and liabilities measured at fair value. This guidance establishes a hierarchical framework for disclosing the observability of the inputs utilized in measuring assets and liabilities at fair value. 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. For additional information see Notes 1, 8 and 10 to the Consolidated Financial Statements included in our 2013 Annual Report on Form 10-K filed with the SEC.
	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.
	Valuation Methodologies for Derivatives
	Oil and Gas Segment:
	•	The commodity option contracts for our Oil and Gas segment are valued using the market approach and can include calls and puts. Fair value was derived using quoted prices from third-party brokers for similar instruments as to quantity and timing. The prices are then validated through third-party sources and therefore support Level 2 disclosure.
	•	The commodity basis swaps for our Oil and Gas segment are valued using the market approach with the instrument’s current forward price strip hedged for the same quantity and date and discounted based on the three-month LIBOR. We utilize observable inputs which support a Level 2 disclosure.
	Utilities Segments:
	•	The commodity contracts for our Utilities Segments, valued using the market approach, include exchange-traded futures, options and basis swaps (Level 2) and OTC basis swaps (Level 3) for natural gas contracts. For Level 2 assets and liabilities, fair value was derived using broker quotes validated by the Chicago Mercantile Exchange pricing for similar instruments. For Level 3 assets and liabilities, fair value was derived using average price quotes from the OTC contract broker and an independent third-party market participant because these instruments are not traded on an exchange.
	Corporate Activities:
	•	The interest rate swaps are valued using the market approach. We establish fair value by obtaining price quotes directly from the counterparty which are based on the floating three-month LIBOR curve for the term of the contract. The fair value obtained from the counterparty is then validated by utilizing a nationally recognized service that obtains observable inputs to compute fair value for the same instrument. In addition, the fair value for the interest rate swap derivatives includes a CVA component. The CVA considers the fair value of the interest rate swap and the probability of default based on the life of the contract. For the probability of a default component, we utilize observable inputs supporting a Level 2 disclosure by using our credit default spread, if available, or a generic credit default spread curve that takes into account our credit ratings.
	Recurring Fair Value Measurements
	There have been no significant transfers between Level 1 and Level 2 derivative balances. Amounts included in cash collateral and counterparty netting in the following tables represent the impact of legally enforceable master netting agreements that allow us to settle positive and negative positions, netting of asset and liability positions permitted in accordance with accounting standards for offsetting as well as cash collateral posted with the same counterparties.
	The following tables set forth by level within the fair value hierarchy our gross assets and gross liabilities and related offsetting as permitted by GAAP that were accounted for at fair value on a recurring basis for derivative instruments. A discussion of fair value of financial instruments is included in Note 10:
		As of September 30, 2014
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			322			—		(322		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			1,545			—		(1,545		)	—
	Commodity derivatives — Utilities	—			4,029			—		(4,029		)	—
	Total	$	—		$	5,896		$	—	$	(5,896	)	$	—
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			487			—		(487		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			865			—		(865		)	—
	Commodity derivatives — Utilities	—			8,679			—		(8,679		)	—
	Interest rate swaps	—			6,670			—		—			6,670
	Total	$	—		$	16,701		$	—	$	(10,031	)	$	6,670
		As of December 31, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			130			—		(75		)	55
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			815			—		(815		)	—
	Commodity derivatives —Utilities	—			3,030			—		(2,368		)	662
	Total	$	—		$	3,975		$	—	$	(3,258	)	$	717
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			1,229			—		(1,229		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			531			—		(531		)	—
	Commodity derivatives — Utilities	—			9,100			—		(9,100		)	—
	Interest rate swaps	—			9,088			—		—			9,088
	Total	$	—		$	19,948		$	—	$	(10,860	)	$	9,088
		As of September 30, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
Options -- Oil	$	—		$	2		$	—	$	—		$	2
Basis Swaps -- Oil	—			51			—		(40		)	11
Options -- Gas	—			—			—		—			—
Basis Swaps -- Gas	—			1,752			—		(1,639		)	113
Commodity derivatives — Utilities	—			2,351			—		(2,351		)	—
Total	$	—		$	4,156		$	—	$	(4,030	)	$	126
Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—		$	142		$	—	$	(77	)	$	65
Basis Swaps -- Oil	—			1,318			—		(1,284		)	34
Options -- Gas	—			—			—		—			—
Basis Swaps -- Gas	—			232			—		(181		)	51
Commodity derivatives — Utilities	—			10,747			—		(10,747		)	—
Interest rate swaps	—			83,142			—		(5,960		)	77,182
Total	$	—		$	95,581		$	—	$	(18,249	)	$	77,332
Fair Value Measures 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 reflecting the netting of asset and liability positions permitted in accordance with accounting standards for offsetting and under terms of our master netting agreements and the impact of legally enforceable master netting agreements that allow us to settle positive and negative positions; however, the amounts do not include net cash collateral on deposit in margin accounts at September 30, 2014, December 31, 2013, and September 30, 2013, to collateralize certain financial instruments, which are included in Derivative assets and/or Derivative liabilities. Therefore, the balances are not indicative of either our actual credit exposure or net economic exposure. Additionally, the amounts below will not agree with the amounts presented on our Condensed Consolidated Balance Sheets, nor will they correspond to the fair value measurements presented in Note 8.
The following tables present the fair value and balance sheet classification of our derivative instruments (in thousands):
As of September 30, 2014
	Balance Sheet Location		Fair Value			Fair Value
			of Asset			of Liability
			Derivatives			Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current		$	1,174		$	—
Commodity derivatives	Derivative assets — non-current		692			—
Commodity derivatives	Derivative liabilities — current		—			497
Commodity derivatives	Derivative liabilities — non-current		—			856
Interest rate swaps	Derivative liabilities — current		—			3,397
Interest rate swaps	Derivative liabilities — non-current		—			3,273
Total derivatives designated as hedges			$	1,866		$	8,023
Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current		$	—		$	—
Commodity derivatives	Derivative assets — non-current		—			—
Commodity derivatives	Derivative liabilities — current		—			48
Commodity derivatives	Derivative liabilities — non-current		—			4,602
Total derivatives not designated as hedges			$	—		$	4,650
As of December 31, 2013
	Balance Sheet Location		Fair Value			Fair Value
			of Asset			of Liability
			Derivatives			Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current		$	248		$	—
Commodity derivatives	Derivative assets — non-current		698			—
Commodity derivatives	Derivative liabilities — current		—			1,541
Commodity derivatives	Derivative liabilities — non-current		—			219
Interest rate swaps	Derivative liabilities — current		—			3,474
Interest rate swaps	Derivative liabilities — non-current		—			5,614
Total derivatives designated as hedges			$	946		$	10,848
Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current		$	662		$	—
Commodity derivatives	Derivative assets — non-current		—			—
Commodity derivatives	Derivative liabilities — current		—			—
Commodity derivatives	Derivative liabilities — non-current		—			6,732
Total derivatives not designated as hedges			$	662		$	6,732
As of September 30, 2013
	Balance Sheet Location		Fair Value			Fair Value
			of Asset			of Liability
			Derivatives			Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current		$	846		$	—
Commodity derivatives	Derivative assets — non-current		959			—
Commodity derivatives	Derivative liabilities — current		—			1,317
Commodity derivatives	Derivative liabilities — non-current		—			375
Interest rate swaps	Derivative liabilities — current		—			7,039
Interest rate swaps	Derivative liabilities — non-current		—			11,388
Total derivatives designated as hedges			$	1,805		$	20,119
Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current		$	—		$	—
Commodity derivatives	Derivative assets — non-current		—			—
Commodity derivatives	Derivative liabilities — current		—			1,795
Commodity derivatives	Derivative liabilities — non-current		—			6,601
Interest rate swaps	Derivative liabilities — current		—			64,715
Interest rate swaps	Derivative liabilities — non-current		—			—
Total derivatives not designated as hedges			$	—		$	73,111

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments [Text Block]	'
	FAIR VALUE OF FINANCIAL INSTRUMENTS
	The estimated fair values of our financial instruments, excluding derivatives which are presented in Note 9, were as follows (in thousands) as of:
		30-Sep-14				31-Dec-13				30-Sep-13
		Carrying		Fair Value		Carrying		Fair Value		Carrying		Fair Value
		Amount				Amount				Amount
	Cash and cash equivalents (a)	$	11,939	$	11,939	$	7,841	$	7,841	$	13,637	$	13,637
	Restricted cash and equivalents (a)	$	1,918	$	1,918	$	2	$	2	$	6,782	$	6,782
	Notes payable (a)	$	184,000	$	184,000	$	82,500	$	82,500	$	138,300	$	138,300
	Long-term debt, including current maturities (b)	$	1,382,519	$	1,547,359	$	1,396,948	$	1,491,422	$	1,211,673	$	1,325,729
	__________
	(a)	Carrying value approximates fair value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates, and therefore is classified in Level 1 in the fair value hierarchy.
	(b)	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

Other_Comprehensive_Income_Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2014
Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Other Comprehensive Income (Loss) [Text Block]	'
	OTHER COMPREHENSIVE INCOME (LOSS)
	The components of the reclassification adjustments, net of tax, included in Other Comprehensive Income (Loss) for the periods were as follows (in thousands):
		Location on the Condensed Consolidated Statements of Income (Loss)	Amount Reclassified from AOCI
			Three Months Ended						Nine Months Ended
			30-Sep-14			30-Sep-13			30-Sep-14			30-Sep-13
	Gains (losses) on cash flow hedges:
	Interest rate swaps	Interest expense	$	925		$	1,844		$	2,745		$	5,460
	Commodity contracts	Revenue	1,135			168			2,697			(896		)
			2,060			2,012			5,442			4,564
	Income tax	Income tax benefit (expense)	(732		)	(586		)	(1,931		)	(1,469		)
	Reclassification adjustments related to cash flow hedges, net of tax		$	1,328		$	1,426		$	3,511		$	3,095
	Amortization of defined benefit plans:
	Prior service cost	Utilities - Operations and maintenance	$	(26	)	$	(31	)	$	(77	)	$	(93	)
		Non-regulated energy operations and maintenance	(22		)	(32		)	(93		)	(96		)
	Actuarial gain (loss)	Utilities - Operations and maintenance	158			425			473			1,267
		Non-regulated energy operations and maintenance	88			275			274			823
			198			637			577			1,901
	Income tax	Income tax benefit (expense)	(69		)	(220		)	(202		)	(663		)
	Reclassification adjustments related to defined benefit plans, net of tax		$	129		$	417		$	375		$	1,238
	Balances by classification included within Accumulated other comprehensive income (loss) on the accompanying Condensed Consolidated Balance Sheets are as follows (in thousands):
		Derivatives Designated as Cash Flow Hedges			Employee Benefit Plans			Total
	Balance as of December 31, 2012	$	(15,713	)	$	(19,775	)	$	(35,488	)
	Other comprehensive income (loss), net of tax	(1,193		)	457			(736		)
	Balance as of March 31, 2013	(16,906		)	(19,318		)	(36,224		)
	Other comprehensive income (loss), net of tax	5,079			364			5,443
	Balance as of June 30, 2013	(11,827		)	(18,954		)	(30,781		)
	Other comprehensive income (loss), net of tax	(657		)	417			(240		)
	Ending Balance September 30, 2013	$	(12,484	)	$	(18,537	)	$	(31,021	)
	Balance as of December 31, 2013	$	(7,133	)	$	(10,289	)	$	(17,422	)
	Other comprehensive income (loss), net of tax	(1,478		)	311			(1,167		)
	Balance as of March 31, 2014	(8,611		)	(9,978		)	(18,589		)
	Other comprehensive income (loss), net of tax	(556		)	(296		)	(852		)
	Balance as of June 30, 2014	(9,167		)	(10,274		)	(19,441		)
	Other comprehensive income (loss), net of tax	4,473			129			4,602
	Ending Balance Sept. 30, 2014	$	(4,694	)	$	(10,145	)	$	(14,839	)

Supplemental_Disclosure_of_Cas

Supplemental Disclosure of Cash Flow Information	9 Months Ended
	Sep. 30, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Disclosure of Cash Flow Information [Text Block]	'
	SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
	Nine months ended	30-Sep-14			30-Sep-13
		(in thousands)
	Non-cash investing and financing activities from continuing operations—
	Property, plant and equipment acquired with accrued liabilities	$	52,484		$	47,214
	Increase (decrease) in capitalized assets associated with asset retirement obligations	$	(2,785	)	$	—
	Cash (paid) refunded during the period for continuing operations—
	Interest (net of amounts capitalized)	$	(46,086	)	$	(57,175	)
	Income taxes, net	$	(396	)	$	(4,924	)

Employee_Benefit_Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Pension and Other Postretirement Benefits Disclosure [Text Block]	'
	EMPLOYEE BENEFIT PLANS
	Defined Benefit Pension Plans
	The components of net periodic benefit cost for the Defined Benefit Pension Plans were as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Service cost	$	1,362		$	1,608		$	4,086		$	4,824
	Interest cost	3,963			3,825			11,889			11,475
	Expected return on plan assets	(4,516		)	(4,654		)	(13,549		)	(13,962		)
	Prior service cost	16			16			47			48
	Net loss (gain)	1,201			3,062			3,604			9,186
	Net periodic benefit cost	$	2,026		$	3,857		$	6,077		$	11,571
	Non-pension Defined Benefit Postretirement Healthcare Plans
	The components of net periodic benefit cost for the Non-pension Defined Benefit Postretirement Healthcare Plans were as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Service cost	$	425		$	419		$	1,275		$	1,257
	Interest cost	480			417			1,439			1,251
	Expected return on plan assets	(21		)	(20		)	(64		)	(60		)
	Prior service cost (benefit)	(107		)	(125		)	(321		)	(375		)
	Net loss (gain)	40			121			120			363
	Net periodic benefit cost	$	817		$	812		$	2,449		$	2,436
	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,
		2014			2013			2014			2013
	Service cost	$	374		$	348		$	1,123		$	1,044
	Interest cost	362			332			1,085			996
	Prior service cost	1			1			2			3
	Net loss (gain)	124			198			373			594
	Net periodic benefit cost	$	861		$	879		$	2,583		$	2,637
	Contributions
	We made contributions to the benefit plans during 2014 and anticipate that we will make contributions to the benefit plans during 2015. Contributions to the Defined Benefit Pension Plans are cash contributions made directly to the Pension Plan Trust accounts. Contributions to the Healthcare and Supplemental Plan are made in the form of benefit payments. Contributions and anticipated contributions are as follows (in thousands):
		Contributions Made			Contributions Made			Additional Contributions			Contributions
		Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014			Anticipated for 2014			Anticipated for 2015
	Defined Benefit Pension Plans	$	10,200		$	10,200		$	—		$	12,500
	Non-pension Defined Benefit Postretirement Healthcare Plans	$	956		$	2,868		$	956		$	3,822
	Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	373		$	1,118		$	373		$	1,494

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies [Text Block]	'
	COMMITMENTS AND CONTINGENCIES
	There have been no significant changes to commitments and contingencies from those previously disclosed in Note 18 of our Notes to the Consolidated Financial Statements in our 2013 Annual Report on Form 10-K except for those described below.
	Power Purchase Agreement
	As disclosed in footnote 16, Black Hills Wyoming sold its CTII 40 MW natural gas-fired generating unit to the City of Gillette, Wyoming on September 3, 2014. Under the terms of the sale, Black Hills Wyoming entered into ancillary agreements, the most significant of which involves a 20-year economy energy PPA. The PPA contains a sharing arrangement where Black Hills Wyoming shares with the City of Gillette savings from wholesale power purchases made on behalf of the City when power costs are less than operating the generating unit. In addition, other ancillary agreements include agreements for Black Hills Wyoming to operate CTII, provide shared facilities, and provide generation dispatch services. Black Hills Wyoming’s previous power sales agreement that sold all of CTII’s output to Cheyenne Light expired on August 31, 2014.
	Natural Gas Delivery Agreement
	In 2012, we entered into a ten-year gas gathering and processing contract for natural gas production from our properties in the Piceance Basin in Colorado, under which we pay a gathering fee per Mcf. The contract requires us to deliver a minimum of 20,000 Mcf per day. This agreement became effective in first quarter of 2014 upon completion of the processing infrastructure capable of handling the committed volumes.
	Reimbursement Agreement
	We have a reimbursement agreement in place with Wells Fargo on behalf of Cheyenne Light for the 2009A bonds of $10 million due in 2027 and the 2009B bonds of $7.0 million due in 2021. In the case of default, we hold the assumption of liability for drawings on Cheyenne Light’s Letter of Credit attached to these bonds.
	Other Commitments
	Construction was completed on Cheyenne Prairie, a 132 MW, $222 million natural gas-fired electric generating facility jointly owned by Cheyenne Light and Black Hills Power. The facility was placed into commercial operation on October 1, 2014. Included in the total cost of Cheyenne Prairie, are contingencies of approximately $2.5 million remaining on contracts pertaining to site finishing, contractor close-outs, and construction management demobilization and cleanup. Resolution of these contingencies is expected in the fourth quarter of 2014.
	Oil Creek Fire
	On June 29, 2012, a forest and grassland fire occurred in the western Black Hills of Wyoming. A state fire investigator concluded that the fire was caused by the failure of a transmission structure owned, operated and maintained by Black Hills Power. On April 16, 2013, a lawsuit was filed in the United States District Court for the District of Wyoming, which forty-seven plaintiffs and the State of Wyoming have now joined, asserting claims for damages against Black Hills Power. The claims include allegations of negligence, negligence per se, common law nuisance, and trespass. In addition to claims for these compensatory damages, the lawsuit seeks recovery of punitive damages. Our investigation of the cause and origin of the fire is ongoing. We have denied and will vigorously defend all claims arising out of the fire, pending the completion of our investigation. We cannot predict the outcome of our investigation, the viability of alleged claims or the outcome of the litigation.
	Civil litigation of this kind, however, is likely to lead to settlement negotiations, including negotiations prompted by pre-trial civil court procedures. We believe such negotiations would effect a settlement of all claims. Regardless of whether the litigation is determined at trial or through settlement, we expect to incur significant investigation, legal and expert services expenses associated with the litigation. We maintain insurance coverage to limit our exposure to losses due to civil liability claims, and related litigation expense. The deductible applicable to some types of claims arising out of this fire is $1.0 million. We expect this coverage to limit our exposure, and we will pursue recoveries to the maximum extent available under the policies. Based upon information currently available, we believe that a loss associated with settlement of pending claims is probable. Accordingly, as of September 30, 2014, we recorded a loss contingency liability related to these claims, and we recorded a receivable for costs we believe are reimbursable and probable of recovery under our insurance coverage. Both of these entries reflect our reasonable estimate of probable future litigation expense and settlement costs; we did not base these contingencies on any determination that it is probable we would be found liable for these claims were they to be litigated.
	Given the uncertainty of litigation, however, a loss related to the fire, the litigation and related claims in excess of the loss we have determined to be probable is reasonably possible. However, we cannot reasonably estimate the amount of such possible loss because our investigation and review of damage claims documentation is ongoing, and there are significant factual and legal issues to be resolved. Further claims may be presented by these and other parties. While we have received claims seeking recovery for fire suppression, reclamation and rehabilitation costs, damage to fencing and other personal property, alleged injury to timber, grass or hay, livestock and related operations, and diminished value of real estate, currently totaling $50 million, we are not yet able, for the reasons described above, to reasonably estimate the amount of any reasonable possible losses in excess of the amount we have accrued. Based upon information currently available, however, management does not expect the outcome of the claims to have a material adverse effect upon our consolidated financial condition, results of operations or cash flows.
	Dividend Restrictions
	Our Revolving Credit Facility and other debt obligations contain restrictions on the payment of cash dividends upon a default or event of default. As of September 30, 2014, we were in compliance with the debt covenants.
	Due to our holding company structure, substantially all of our operating cash flows are provided by dividends paid or distributions made by our subsidiaries. The cash to pay dividends to our stockholders is derived from these cash flows. As a result, certain statutory limitations or regulatory or financing agreements could affect the levels of distributions allowed to be made by our subsidiaries. The following restrictions on distributions from our subsidiaries existed at September 30, 2014:
	•	Our utilities are generally limited to the amount of dividends allowed to be paid to us as a utility holding company under the Federal Power Act and settlement agreements with state regulatory jurisdictions. As of September 30, 2014, the restricted net assets at our Utilities Group were approximately $73 million.

Guarantees

Guarantees	9 Months Ended
	Sep. 30, 2014
Guarantees [Abstract]	'
Guarantees [Text Block]	'
	GUARANTEES
	We have entered into various agreements providing financial or performance assurance to third parties on behalf of certain of our subsidiaries. The agreements include indemnification for reclamation and surety bonds.
	We had the following guarantees in place (in thousands):
		Maximum Exposure at
	Nature of Guarantee	30-Sep-14		Expiration
	Indemnification for subsidiary reclamation/surety bonds (a)	$	63,900	Ongoing
	_______________________
	(a)	We have guarantees in place for reclamation and surety bonds for our subsidiaries. The guarantees were entered into in the normal course of business. To the extent liabilities are incurred as a result of activities covered by the surety bonds, such liabilities are included in our Condensed Consolidated Balance Sheets.
	During the second quarter of 2014, guarantees of Black Hills Utility Holdings’ payment obligations up to $70 million arising from commodity transactions for natural gas supply were removed, primarily due to improvement of the corporate credit rating, as well as the conversion of certain guarantees to letters of credit.

Sale_of_Operating_Asset

Sale of Operating Asset	9 Months Ended
	Sep. 30, 2014
Sale of Operating Asset [Abstract]	'
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	'
	SALE OF OPERATING ASSET
	On September 3, 2014, Black Hills Wyoming closed the sale of its 40 MW CTII natural-gas fired generating unit to the City of Gillette, Wyoming for approximately $22 million, upon expiration on August 31, 2014 of the PPA with Cheyenne Light. Consideration for the sale included ancillary agreements, the most significant of which includes Black Hills Wyoming providing services to the City of Gillette through an economy energy PPA over a term of 20 years. Black Hills Wyoming will recognize a $4.9 million gain on sale over the 20 year term of the agreements. The deferred gain is recorded in Other deferred credits and other liabilities at September 30, 2014 on the accompanying Condensed Consolidated Balance Sheet.

Subsequent_Event

Subsequent Event	9 Months Ended
	Sep. 30, 2014
Subsequent Event [Abstract]	'
Subsequent Events [Text Block]	'
	SUBSEQUENT EVENT
	Long-Term Debt
	On October 1, 2014, Black Hills Power and Cheyenne Light sold $160 million of first mortgage bonds in a private placement to provide permanent financing for Cheyenne Prairie. Black Hills Power issued $85 million of 4.43% coupon first mortgage bonds due October 20, 2044, and Cheyenne Light issued $75 million of 4.53% coupon first mortgage bonds due October 20, 2044. Proceeds from Black Hills Power’s bond sale also funded the early redemption of its 5.35% $12 million pollution control revenue bonds, originally due October 1, 2024.

Business_Segment_Information_T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting Information, Additional Information [Abstract]	'
Schedule of Segment Reporting Information [Table Text Block]	'
	Segment information and Corporate activities included in the accompanying Condensed Consolidated Statements of Income (Loss) were as follows (in thousands):
	Three Months Ended September 30, 2014		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	171,395		$	3,156			$	18,154
	Gas		78,735			—				1,597
	Non-regulated Energy:
	Power Generation		1,602			20,419				7,829
	Coal Mining		6,884			8,689				2,638
	Oil and Gas		13,471			—				(3,110		)
	Corporate activities		—			—				(272		)
	Inter-company eliminations		—			(32,264		)		—
	Total		$	272,087		$	—			$	26,836
	Three Months Ended September 30, 2013		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	169,401		$	2,003			$	15,097
	Gas		67,792			—				(1,450		)
	Non-regulated Energy:
	Power Generation		1,575			20,393				6,707
	Coal Mining		6,713			8,604				2,142
	Oil and Gas		14,426			—				(1,682		)
	Corporate activities (a)		—			—				2,310
	Inter-company eliminations		—			(31,000		)		—
	Total		$	259,907		$	—			$	23,124
	Nine Months Ended September 30, 2014		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	508,230		$	10,307			$	44,156
	Gas		440,571			—				28,289
	Non-regulated Energy:
	Power Generation		4,138			62,211				23,096
	Coal Mining		19,085			26,637				7,118
	Oil and Gas		43,469			—				(6,792		)
	Corporate activities		—			—				(1,093		)
	Inter-company eliminations		—			(99,155		)		—
	Total		$	1,015,493		$	—			$	94,774
	Nine Months Ended September 30, 2013		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	482,222		$	9,844			$	38,063
	Gas		373,440			—				20,225
	Non-regulated Energy:
	Power Generation		3,628			58,825				17,382
	Coal Mining		19,530			23,688				5,180
	Oil and Gas		41,584			—				(3,699		)
	Corporate activities (a)		—			—				19,688
	Inter-company eliminations		—			(92,357		)		—
	Total		$	920,404		$	—			$	96,839
	__________
	(a)	Corporate activities include a $2.0 million and a $19 million after-tax non-cash mark-to-market gain on certain interest rate swaps for the three and nine months ended September 30, 2013, respectively.
Reconciliation of Assets from Segment to Consolidated [Table Text Block]	'
	Segment information and Corporate balances included in the accompanying Condensed Consolidated Balance Sheets were as follows (in thousands):
	Total Assets (net of inter-company eliminations) as of:	30-Sep-14			31-Dec-13				30-Sep-13
	Utilities:
	Electric (a)	$	2,671,601		$	2,525,947			$	2,464,123
	Gas	827,069			805,617				757,746
	Non-regulated Energy:
	Power Generation (a)	64,359			95,692				102,331
	Coal Mining	74,130			78,825				82,155
	Oil and Gas	330,781			288,366				264,785
	Corporate activities	105,322			80,731				130,100
	Total assets	$	4,073,262		$	3,875,178			$	3,801,240
	__________
	(a)	The PPA under which Black Hills Colorado IPP provides generation to support Colorado Electric customers from the Pueblo Airport Generation Station is accounted for as a capital lease. As such, assets owned by our Power Generation segment are recorded at Colorado Electric under accounting for a capital lease.

Accounts_Receivable_Tables

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Schedule of Accounts Receivable [Table Text Block]	'
	Following is a summary of Accounts receivable, net included in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:
		Accounts		Unbilled		Less Allowance for			Accounts
	30-Sep-14	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	53,717	$	21,485	$	(724	)	$	74,478
	Gas Utilities	23,409		13,218		(740		)	35,887
	Power Generation	1,368		—		—			1,368
	Coal Mining	2,563		—		—			2,563
	Oil and Gas	7,657		—		(13		)	7,644
	Corporate	1,459		—		—			1,459
	Total	$	90,173	$	34,703	$	(1,477	)	$	123,399
		Accounts		Unbilled		Less Allowance for			Accounts
	31-Dec-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	52,437	$	23,823	$	(666	)	$	75,594
	Gas Utilities	49,162		41,195		(558		)	89,799
	Power Generation	1,722		—		—			1,722
	Coal Mining	1,711		—		—			1,711
	Oil and Gas	8,156		—		(13		)	8,143
	Corporate	604		—		—			604
	Total	$	113,792	$	65,018	$	(1,237	)	$	177,573
		Accounts		Unbilled		Less Allowance for			Accounts
	30-Sep-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	49,254	$	20,153	$	(648	)	$	68,759
	Gas Utilities	20,693		11,877		(542		)	32,028
	Power Generation	3		—		—			3
	Coal Mining	2,677		—		—			2,677
	Oil and Gas	8,463		—		(19		)	8,444
	Corporate	2,226		—		—			2,226
	Total	$	83,316	$	32,030	$	(1,209	)	$	114,137

Regulatory_Assets_and_Liabilit

Regulatory Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2014
Regulatory Assets and Liabilities Disclosure [Abstract]	'
Schedule of Regulatory Assets and Liabilities [Table Text Block]	'
	We had the following regulatory assets and liabilities (in thousands):
		Maximum	As of		As of		As of
		Amortization (in years)	30-Sep-14		31-Dec-13		30-Sep-13
	Regulatory assets
	Deferred energy and fuel cost adjustments - current (a)(d)	1	$	26,211	$	16,775	$	17,925
	Deferred gas cost adjustments and natural gas price derivatives (a)(d)	7	49,870		12,366		16,845
	AFUDC (b)	45	12,411		12,315		12,398
	Employee benefit plans (c)	13	64,908		67,059		114,386
	Environmental (a)	subject to approval	1,314		1,800		1,800
	Asset retirement obligations (a)	44	3,282		3,266		3,262
	Bond issue cost (a)	24	3,311		3,419		3,454
	Renewable energy standard adjustment (a)	5	12,007		14,186		14,936
	Flow through accounting (c)	35	25,157		20,916		19,222
	Other regulatory assets (a)	15	10,395		10,546		9,099
			$	208,866	$	162,648	$	213,327
	Regulatory liabilities
	Deferred energy and gas costs (a)	1	$	5,535	$	11,708	$	14,032
	Employee benefit plans (c)	13	34,409		34,431		60,707
	Cost of removal (a)	44	71,362		64,970		62,069
	Other regulatory liabilities (c)	25	8,378		9,047		9,629
			$	119,684	$	120,156	$	146,437
	__________
	(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, respectively.
	(d)	Our deferred energy, fuel cost, and gas cost adjustments represent the cost of electricity and gas delivered to our electric and gas utility customers that is either higher or lower than current rates and will be recovered or refunded in future rates. Increases in the current year balances as of September 30, 2014 are primarily due to higher natural gas prices driven by demand and market conditions during our peak winter heating season. Our electric and gas utilities file periodic quarterly, semi-annual, and/or annual filings to recover these costs based on the respective cost mechanisms approved by their applicable state utility commissions.

Materials_Supplies_and_Fuel_Ta

Materials, Supplies and Fuel (Tables)	9 Months Ended
	Sep. 30, 2014
Inventory, Net [Abstract]	'
Materials, Supplies and Fuel [Table Text Block]	'
	The following amounts by major classification are included in Materials, supplies and fuel in the accompanying Condensed Consolidated Balance Sheets (in thousands) as of:
		30-Sep-14		31-Dec-13		30-Sep-13
	Materials and supplies	$	52,682	$	50,196	$	50,564
	Fuel - Electric Utilities	7,108		6,213		6,384
	Natural gas in storage held for distribution	45,936		32,069		38,282
	Total materials, supplies and fuel	$	105,726	$	88,478	$	95,230

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Earnings Per Share Reconciliation [Table Text Block]	'
	A reconciliation of share amounts used to compute Earnings (loss) per share in the accompanying Condensed Consolidated Statements of Income (loss) is as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014		2013
	Net income (loss) available for common stock	$	26,836		$	23,124		$	94,774	$	96,839
	Weighted average shares - basic	44,415			44,201			44,382		44,143
	Dilutive effect of:
	Equity compensation	193			256			202		252
	Weighted average shares - diluted	44,608			44,457			44,584		44,395
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	'
	The following outstanding securities were not included in the computation of diluted earnings per share as their effect would have been anti-dilutive (in thousands):
		Three Months Ended September 30,					Nine Months Ended September 30,
		2014		2013			2014	2013
	Equity compensation	99		—			75	9
	Anti-dilutive shares	99		—			75	9

Notes_Payable_and_Current_Matu1

Notes Payable and Current Maturities of Long-term Debt (Tables)

9 Months Ended

Sep. 30, 2014

Debt Disclosure [Abstract]

'

Schedule of Short-term Debt [Table Text Block]

'

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

30-Sep-14

31-Dec-13

30-Sep-13

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Revolving Credit Facility

$

184,000

$

31,726

$

82,500

$

22,100

$

138,300

$

53,137

Credit Facility and Short Term Debt Covenants [Table Text Block]

'

Our Revolving Credit Facility and our Term Loan require compliance with the following financial covenant at the end of each quarter:

As of September 30, 2014

Covenant Requirement

Recourse Leverage Ratio

54%

Less than

65%

Risk_Management_Activities_Tab

Risk Management Activities (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative [Line Items]	'
Schedule of Derivative Instruments [Table Text Block]	'
	The contract or notional amounts, terms of our interest rate swaps and the interest rate swaps balances reflected on the Condensed Consolidated Balance Sheets were as follows (dollars in thousands) as of:
		30-Sep-14				31-Dec-13				30-Sep-13
		Interest Rate				Interest Rate				Interest Rate			De-designated
		Swaps (a)				Swaps (a)				Swaps (b)			Interest Rate
													Swaps (c)
	Notional	$	75,000			$	75,000			$	150,000		$	250,000
	Weighted average fixed interest rate	4.97		%		4.97		%		5.04		%	5.67		%
	Maximum terms in years	2.25				3				3.25			0.25
	Derivative liabilities, current	$	3,397			$	3,474			$	7,039		$	58,755
	Derivative liabilities, non-current	$	3,273			$	5,614			$	11,388		$	—
	__________
	(a)	These swaps are designated to borrowings on our Revolving Credit Facility, and are priced using three-month LIBOR, matching the floating portion of the related debt.
	(b)	At September 30, 2013, $75 million of these interest rate swaps was designated to borrowings on our Revolving Credit Facility and $75 million was designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps were priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that was designated to Black Hills Wyoming was settled during the fourth quarter of 2013 upon repayment of the Black Hills Wyoming project financing.
	(c)	These swaps were settled during the fourth quarter of 2013.
Derivative Instruments, Gain (Loss) [Table Text Block]	'
	The impacts of cash flow hedges on our Condensed Consolidated Statements of Income (Loss) were as follows (in thousands):
	Three Months Ended September 30, 2014
	Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
			Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
			Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
			in AOCI				from AOCI		from AOCI				in Income		Income on
			Derivative				into Income		into Income				on Derivative		Derivative
			(Effective				(Effective		(Effective				(Ineffective		(Ineffective
			Portion)				Portion)		Portion)				Portion)		Portion)
	Interest rate swaps		$	152			Interest expense		$	(925	)				$	—
	Commodity derivatives		4,833				Revenue		(1,135		)				—
	Total		$	4,985					$	(2,060	)				$	—
	Three Months Ended September 30, 2013
	Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
			Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
			Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
			in AOCI				from AOCI		from AOCI				in Income		Income on
			Derivative				into Income		into Income				on Derivative		Derivative
			(Effective				(Effective		(Effective				(Ineffective		(Ineffective
			Portion)				Portion)		Portion)				Portion)		Portion)
	Interest rate swaps		$	(907	)		Interest expense		$	(1,844	)				$	—
	Commodity derivatives		(2,140		)		Revenue		(168		)				—
	Total		$	(3,047	)				$	(2,012	)				$	—
	Nine Months Ended September 30, 2014
	Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
			Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
			Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
			in AOCI				from AOCI		from AOCI				in Income		Income on
			Derivative				into Income		into Income				on Derivative		Derivative
			(Effective				(Effective		(Effective				(Ineffective		(Ineffective
			Portion)				Portion)		Portion)				Portion)		Portion)
	Interest rate swaps		$	(277	)		Interest expense		$	(2,745	)				$	—
	Commodity derivatives		(1,376		)		Revenue		(2,697		)				—
	Total		$	(1,653	)				$	(5,442	)				$	—
	Nine Months Ended September 30, 2013
	Derivatives in Cash Flow Hedging Relationships		Amount of				Location		Amount of				Location of		Amount of
			Gain/(Loss)				of Gain/(Loss)		Reclassified				Gain/(Loss)		Gain/(Loss)
			Recognized				Reclassified		Gain/(Loss)				Recognized		Recognized in
			in AOCI				from AOCI		from AOCI				in Income		Income on
			Derivative				into Income		into Income				on Derivative		Derivative
			(Effective				(Effective		(Effective				(Ineffective		(Ineffective
			Portion)				Portion)		Portion)				Portion)		Portion)
	Interest rate swaps		$	141			Interest expense		$	(5,460	)				$	—
	Commodity derivatives		86				Revenue		896						—
	Total		$	227					$	(4,564	)				$	—
Oil and Gas [Member]	'
Derivative [Line Items]	'
Schedule of Derivative Instruments [Table Text Block]	'
	The contract or notional amounts, terms of our commodity derivatives, and the derivative balances for our Oil and Gas segment reflected on the Condensed Consolidated Balance Sheets were as follows (dollars in thousands) as of:
		30-Sep-14							31-Dec-13							30-Sep-13
		Crude Oil Futures, Swaps and Options			Natural Gas Futures and Swaps				Crude Oil Futures, Swaps and Options			Natural Gas Futures and Swaps				Crude Oil Futures, Swaps and Options		Natural Gas Futures and Swaps
	Notional (a)	391,500			7,930,000				412,500			7,082,500				499,500		9,874,000
	Maximum terms in months (b)	1			1				3			1				3		1
	Derivative assets, current	$	—		$	—			$	55		$	—			$	13	$	113
	Derivative assets, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	Derivative liabilities, current	$	—		$	—			$	—		$	—			$	98	$	52
	Derivative liabilities, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	__________
	(a)	Crude oil in Bbls, natural gas in MMBtus.
	(b)	Refers to the tenor of the derivative instrument. Assets and liabilities are classified as current/non-current based on the production month hedged and the corresponding settlement of the derivative instrument.
Utilities Group [Member]	'
Derivative [Line Items]	'
Schedule of Derivative Instruments [Table Text Block]	'
	We had the following derivative balances related to the hedges in our Utilities reflected in our Condensed Consolidated Balance Sheets as of (in thousands):
		30-Sep-14			31-Dec-13			30-Sep-13
	Derivative assets, current	$	—		$	662		$	—
	Derivative assets, non-current	$	—		$	—		$	—
	Derivative liabilities, non-current	$	—		$	—		$	—
	Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	7,470		$	7,567		$	10,652
Contract or Notional Amounts and Terms of Commodity Derivatives[Table Text Block]	'
	The contract or notional amounts and terms of the natural gas derivative commodity instruments held at our Utilities were as follows, as of:
		30-Sep-14					31-Dec-13					30-Sep-13
		Notional			Maximum		Notional			Maximum		Notional			Maximum
		(MMBtus)			Term		(MMBtus)			Term		(MMBtus)			Term
					(months) (a)					(months) (a)					(months) (a)
	Natural gas futures purchased	16,290,000			74		17,930,000			84		14,010,000			74
	Natural gas options purchased	7,070,000			6		3,890,000			8		6,810,000			6
	Natural gas basis swaps purchased	12,025,000			63		14,785,000			60		9,790,000			63

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Fair Value Hierarchy, Measured on Recurring Basis [Table Text Block]	'
	The following tables set forth by level within the fair value hierarchy our gross assets and gross liabilities and related offsetting as permitted by GAAP that were accounted for at fair value on a recurring basis for derivative instruments. A discussion of fair value of financial instruments is included in Note 10:
		As of September 30, 2014
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			322			—		(322		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			1,545			—		(1,545		)	—
	Commodity derivatives — Utilities	—			4,029			—		(4,029		)	—
	Total	$	—		$	5,896		$	—	$	(5,896	)	$	—
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			487			—		(487		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			865			—		(865		)	—
	Commodity derivatives — Utilities	—			8,679			—		(8,679		)	—
	Interest rate swaps	—			6,670			—		—			6,670
	Total	$	—		$	16,701		$	—	$	(10,031	)	$	6,670
		As of December 31, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			130			—		(75		)	55
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			815			—		(815		)	—
	Commodity derivatives —Utilities	—			3,030			—		(2,368		)	662
	Total	$	—		$	3,975		$	—	$	(3,258	)	$	717
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			1,229			—		(1,229		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			531			—		(531		)	—
	Commodity derivatives — Utilities	—			9,100			—		(9,100		)	—
	Interest rate swaps	—			9,088			—		—			9,088
	Total	$	—		$	19,948		$	—	$	(10,860	)	$	9,088
		As of September 30, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	2		$	—	$	—		$	2
	Basis Swaps -- Oil	—			51			—		(40		)	11
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			1,752			—		(1,639		)	113
	Commodity derivatives — Utilities	—			2,351			—		(2,351		)	—
	Total	$	—		$	4,156		$	—	$	(4,030	)	$	126
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	142		$	—	$	(77	)	$	65
	Basis Swaps -- Oil	—			1,318			—		(1,284		)	34
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			232			—		(181		)	51
	Commodity derivatives — Utilities	—			10,747			—		(10,747		)	—
	Interest rate swaps	—			83,142			—		(5,960		)	77,182
Total	$	—		$	95,581		$	—	$	(18,249	)	$	77,332
Schedule of Derivative Instruments Balance Sheet Location [Table Text Block]	'
	The following tables present the fair value and balance sheet classification of our derivative instruments (in thousands):
	As of September 30, 2014
		Balance Sheet Location		Fair Value			Fair Value
				of Asset			of Liability
				Derivatives			Derivatives
	Derivatives designated as hedges:
	Commodity derivatives	Derivative assets — current		$	1,174		$	—
	Commodity derivatives	Derivative assets — non-current		692			—
	Commodity derivatives	Derivative liabilities — current		—			497
	Commodity derivatives	Derivative liabilities — non-current		—			856
	Interest rate swaps	Derivative liabilities — current		—			3,397
	Interest rate swaps	Derivative liabilities — non-current		—			3,273
	Total derivatives designated as hedges			$	1,866		$	8,023
	Derivatives not designated as hedges:
	Commodity derivatives	Derivative assets — current		$	—		$	—
	Commodity derivatives	Derivative assets — non-current		—			—
	Commodity derivatives	Derivative liabilities — current		—			48
	Commodity derivatives	Derivative liabilities — non-current		—			4,602
	Total derivatives not designated as hedges			$	—		$	4,650
	As of December 31, 2013
		Balance Sheet Location		Fair Value			Fair Value
				of Asset			of Liability
				Derivatives			Derivatives
	Derivatives designated as hedges:
	Commodity derivatives	Derivative assets — current		$	248		$	—
	Commodity derivatives	Derivative assets — non-current		698			—
	Commodity derivatives	Derivative liabilities — current		—			1,541
	Commodity derivatives	Derivative liabilities — non-current		—			219
	Interest rate swaps	Derivative liabilities — current		—			3,474
	Interest rate swaps	Derivative liabilities — non-current		—			5,614
	Total derivatives designated as hedges			$	946		$	10,848
	Derivatives not designated as hedges:
	Commodity derivatives	Derivative assets — current		$	662		$	—
	Commodity derivatives	Derivative assets — non-current		—			—
	Commodity derivatives	Derivative liabilities — current		—			—
	Commodity derivatives	Derivative liabilities — non-current		—			6,732
	Total derivatives not designated as hedges			$	662		$	6,732
	As of September 30, 2013
		Balance Sheet Location		Fair Value			Fair Value
				of Asset			of Liability
				Derivatives			Derivatives
	Derivatives designated as hedges:
	Commodity derivatives	Derivative assets — current		$	846		$	—
	Commodity derivatives	Derivative assets — non-current		959			—
	Commodity derivatives	Derivative liabilities — current		—			1,317
	Commodity derivatives	Derivative liabilities — non-current		—			375
	Interest rate swaps	Derivative liabilities — current		—			7,039
	Interest rate swaps	Derivative liabilities — non-current		—			11,388
	Total derivatives designated as hedges			$	1,805		$	20,119
	Derivatives not designated as hedges:
	Commodity derivatives	Derivative assets — current		$	—		$	—
	Commodity derivatives	Derivative assets — non-current		—			—
	Commodity derivatives	Derivative liabilities — current		—			1,795
	Commodity derivatives	Derivative liabilities — non-current		—			6,601
	Interest rate swaps	Derivative liabilities — current		—			64,715
	Interest rate swaps	Derivative liabilities — non-current		—			—
	Total derivatives not designated as hedges			$	—		$	73,111

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments [Table Text Block]	'
	The estimated fair values of our financial instruments, excluding derivatives which are presented in Note 9, were as follows (in thousands) as of:
		30-Sep-14				31-Dec-13				30-Sep-13
		Carrying		Fair Value		Carrying		Fair Value		Carrying		Fair Value
		Amount				Amount				Amount
	Cash and cash equivalents (a)	$	11,939	$	11,939	$	7,841	$	7,841	$	13,637	$	13,637
	Restricted cash and equivalents (a)	$	1,918	$	1,918	$	2	$	2	$	6,782	$	6,782
	Notes payable (a)	$	184,000	$	184,000	$	82,500	$	82,500	$	138,300	$	138,300
	Long-term debt, including current maturities (b)	$	1,382,519	$	1,547,359	$	1,396,948	$	1,491,422	$	1,211,673	$	1,325,729
	__________
	(a)	Carrying value approximates fair value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates, and therefore is classified in Level 1 in the fair value hierarchy.
	(b)	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

Other_Comprehensive_Income_Los1

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2014
Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
	The components of the reclassification adjustments, net of tax, included in Other Comprehensive Income (Loss) for the periods were as follows (in thousands):
		Location on the Condensed Consolidated Statements of Income (Loss)	Amount Reclassified from AOCI
			Three Months Ended						Nine Months Ended
			30-Sep-14			30-Sep-13			30-Sep-14			30-Sep-13
	Gains (losses) on cash flow hedges:
	Interest rate swaps	Interest expense	$	925		$	1,844		$	2,745		$	5,460
	Commodity contracts	Revenue	1,135			168			2,697			(896		)
			2,060			2,012			5,442			4,564
	Income tax	Income tax benefit (expense)	(732		)	(586		)	(1,931		)	(1,469		)
	Reclassification adjustments related to cash flow hedges, net of tax		$	1,328		$	1,426		$	3,511		$	3,095
	Amortization of defined benefit plans:
	Prior service cost	Utilities - Operations and maintenance	$	(26	)	$	(31	)	$	(77	)	$	(93	)
		Non-regulated energy operations and maintenance	(22		)	(32		)	(93		)	(96		)
	Actuarial gain (loss)	Utilities - Operations and maintenance	158			425			473			1,267
		Non-regulated energy operations and maintenance	88			275			274			823
			198			637			577			1,901
	Income tax	Income tax benefit (expense)	(69		)	(220		)	(202		)	(663		)
	Reclassification adjustments related to defined benefit plans, net of tax		$	129		$	417		$	375		$	1,238
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
	Balances by classification included within Accumulated other comprehensive income (loss) on the accompanying Condensed Consolidated Balance Sheets are as follows (in thousands):
		Derivatives Designated as Cash Flow Hedges			Employee Benefit Plans			Total
	Balance as of December 31, 2012	$	(15,713	)	$	(19,775	)	$	(35,488	)
	Other comprehensive income (loss), net of tax	(1,193		)	457			(736		)
	Balance as of March 31, 2013	(16,906		)	(19,318		)	(36,224		)
	Other comprehensive income (loss), net of tax	5,079			364			5,443
	Balance as of June 30, 2013	(11,827		)	(18,954		)	(30,781		)
	Other comprehensive income (loss), net of tax	(657		)	417			(240		)
	Ending Balance September 30, 2013	$	(12,484	)	$	(18,537	)	$	(31,021	)
	Balance as of December 31, 2013	$	(7,133	)	$	(10,289	)	$	(17,422	)
	Other comprehensive income (loss), net of tax	(1,478		)	311			(1,167		)
	Balance as of March 31, 2014	(8,611		)	(9,978		)	(18,589		)
	Other comprehensive income (loss), net of tax	(556		)	(296		)	(852		)
	Balance as of June 30, 2014	(9,167		)	(10,274		)	(19,441		)
	Other comprehensive income (loss), net of tax	4,473			129			4,602
	Ending Balance Sept. 30, 2014	$	(4,694	)	$	(10,145	)	$	(14,839	)

Supplemental_Disclosure_of_Cas1

Supplemental Disclosure of Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Disclosure of Cash Flow Information [Table Text Block]	'
	Nine months ended	30-Sep-14			30-Sep-13
		(in thousands)
	Non-cash investing and financing activities from continuing operations—
	Property, plant and equipment acquired with accrued liabilities	$	52,484		$	47,214
	Increase (decrease) in capitalized assets associated with asset retirement obligations	$	(2,785	)	$	—
	Cash (paid) refunded during the period for continuing operations—
	Interest (net of amounts capitalized)	$	(46,086	)	$	(57,175	)
	Income taxes, net	$	(396	)	$	(4,924	)

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2014
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]	'
Schedule of Net Benefit Costs [Table Text Block]	'
	The components of net periodic benefit cost for the Defined Benefit Pension Plans were as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Service cost	$	1,362		$	1,608		$	4,086		$	4,824
	Interest cost	3,963			3,825			11,889			11,475
	Expected return on plan assets	(4,516		)	(4,654		)	(13,549		)	(13,962		)
	Prior service cost	16			16			47			48
	Net loss (gain)	1,201			3,062			3,604			9,186
	Net periodic benefit cost	$	2,026		$	3,857		$	6,077		$	11,571
	Non-pension Defined Benefit Postretirement Healthcare Plans
	The components of net periodic benefit cost for the Non-pension Defined Benefit Postretirement Healthcare Plans were as follows (in thousands):
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
	Service cost	$	425		$	419		$	1,275		$	1,257
	Interest cost	480			417			1,439			1,251
	Expected return on plan assets	(21		)	(20		)	(64		)	(60		)
	Prior service cost (benefit)	(107		)	(125		)	(321		)	(375		)
	Net loss (gain)	40			121			120			363
	Net periodic benefit cost	$	817		$	812		$	2,449		$	2,436
	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,
		2014			2013			2014			2013
	Service cost	$	374		$	348		$	1,123		$	1,044
	Interest cost	362			332			1,085			996
	Prior service cost	1			1			2			3
	Net loss (gain)	124			198			373			594
	Net periodic benefit cost	$	861		$	879		$	2,583		$	2,637
Schedule of Defined Benefit Plans Contributions [Table Text Block]	'
	Contributions and anticipated contributions are as follows (in thousands):
		Contributions Made			Contributions Made			Additional Contributions			Contributions
		Three Months Ended September 30, 2014			Nine Months Ended September 30, 2014			Anticipated for 2014			Anticipated for 2015
	Defined Benefit Pension Plans	$	10,200		$	10,200		$	—		$	12,500
	Non-pension Defined Benefit Postretirement Healthcare Plans	$	956		$	2,868		$	956		$	3,822
	Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	373		$	1,118		$	373		$	1,494

Guarantees_Tables

Guarantees (Tables)	9 Months Ended
	Sep. 30, 2014
Guarantees [Abstract]	'
Schedule of Guarantor Obligations [Table Text Block]	'
	We had the following guarantees in place (in thousands):
		Maximum Exposure at
	Nature of Guarantee	30-Sep-14		Expiration
	Indemnification for subsidiary reclamation/surety bonds (a)	$	63,900	Ongoing
	_______________________
	(a)	We have guarantees in place for reclamation and surety bonds for our subsidiaries. The guarantees were entered into in the normal course of business. To the extent liabilities are incurred as a result of activities covered by the surety bonds, such liabilities are included in our Condensed Consolidated Balance Sheets.

Information_Relating_to_Segmen

Information Relating to Segment Statement of Income (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013		Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	$272,087,000	$259,907,000		$1,015,493,000	$920,404,000
Net Income (Loss)	26,836,000	23,124,000		94,774,000	96,839,000
Mark-to-market gain (loss) on certain interest rate swaps, net of tax	'	2,000,000		'	19,000,000
Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	-32,264,000	-31,000,000		-99,155,000	-92,357,000
Net Income (Loss)	0	0		0	0
Corporate activities[Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	0	0		0	0
Net Income (Loss)	-272,000	2,310,000	[1]	-1,093,000	19,688,000	[1]
Consolidation, Eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	0	0		0	0
Electric Utilities [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	171,395,000	169,401,000		508,230,000	482,222,000
Net Income (Loss)	18,154,000	15,097,000		44,156,000	38,063,000
Electric Utilities [Member] | Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	3,156,000	2,003,000		10,307,000	9,844,000
Gas Utilities [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	78,735,000	67,792,000		440,571,000	373,440,000
Net Income (Loss)	1,597,000	-1,450,000		28,289,000	20,225,000
Gas Utilities [Member] | Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	0	0		0	0
Power Generation [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	1,602,000	1,575,000		4,138,000	3,628,000
Net Income (Loss)	7,829,000	6,707,000		23,096,000	17,382,000
Power Generation [Member] | Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	20,419,000	20,393,000		62,211,000	58,825,000
Coal Mining [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	6,884,000	6,713,000		19,085,000	19,530,000
Net Income (Loss)	2,638,000	2,142,000		7,118,000	5,180,000
Coal Mining [Member] | Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	8,689,000	8,604,000		26,637,000	23,688,000
Oil and Gas [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	13,471,000	14,426,000		43,469,000	41,584,000
Net Income (Loss)	-3,110,000	-1,682,000		-6,792,000	-3,699,000
Oil and Gas [Member] | Inter-company eliminations [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	$0	$0		$0	$0
[1]	Corporate activities include a $2.0 million and a $19 million after-tax non-cash mark-to-market gain on certain interest rate swaps for the three and nine months ended September 30, 2013, respectively.

Segment_and_Corporate_Assets_D

Segment and Corporate Assets (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	$4,073,262		$3,875,178		$3,801,240
Corporate activities[Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	105,322		80,731		130,100
Electric Utilities [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	2,671,601	[1]	2,525,947	[1]	2,464,123	[1]
Gas Utilities [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	827,069		805,617		757,746
Power Generation [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	64,359	[1]	95,692	[1]	102,331	[1]
Coal Mining [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	74,130		78,825		82,155
Oil and Gas [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	$330,781		$288,366		$264,785
[1]	The PPA under which Black Hills Colorado IPP provides generation to support Colorado Electric customers from the Pueblo Airport Generation Station is accounted for as a capital lease. As such, assets owned by our Power Generation segment are recorded at Colorado Electric under accounting for a capital lease.

Accounts_Receivable_Details

Accounts Receivable (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	($1,477)	($1,237)	($1,209)
Accounts receivable, net	123,399	177,573	114,137
Corporate[Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	1,459	604	2,226
Electric Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-724	-666	-648
Accounts receivable, net	74,478	75,594	68,759
Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-740	-558	-542
Accounts receivable, net	35,887	89,799	32,028
Power Generation [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	1,368	1,722	3
Coal Mining [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	2,563	1,711	2,677
Oil and Gas [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-13	-13	-19
Accounts receivable, net	7,644	8,143	8,444
Billed Revenues [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	90,173	113,792	83,316
Billed Revenues [Member] | Corporate[Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	1,459	604	2,226
Billed Revenues [Member] | Electric Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	53,717	52,437	49,254
Billed Revenues [Member] | Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	23,409	49,162	20,693
Billed Revenues [Member] | Power Generation [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	1,368	1,722	3
Billed Revenues [Member] | Coal Mining [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	2,563	1,711	2,677
Billed Revenues [Member] | Oil and Gas [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	7,657	8,156	8,463
Unbilled Revenues [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	34,703	65,018	32,030
Unbilled Revenues [Member] | Corporate[Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	0	0	0
Unbilled Revenues [Member] | Electric Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	21,485	23,823	20,153
Unbilled Revenues [Member] | Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	13,218	41,195	11,877
Unbilled Revenues [Member] | Power Generation [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	0	0	0
Unbilled Revenues [Member] | Coal Mining [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	0	0	0
Unbilled Revenues [Member] | Oil and Gas [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	$0	$0	$0

Regulatory_Assets_and_Liabilit1

Regulatory Assets and Liabilities (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets	$208,866		$162,648		$213,327
Regulatory Liabilities	119,684		120,156		146,437
Deferred energy and gas costs	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P1Y		'		'
Regulatory Liabilities	5,535	[1]	11,708	[1]	14,032	[1]
Employee benefit plans	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P13Y		'		'
Regulatory Liabilities	34,409	[2]	34,431	[2]	60,707	[2]
Cost of removal	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P44Y		'		'
Regulatory Liabilities	71,362	[1]	64,970	[1]	62,069	[1]
Other regulatory liabilities	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P25Y		'		'
Regulatory Liabilities	8,378	[2]	9,047	[2]	9,629	[2]
Deferred energy and fuel cost adjustments - current	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P1Y		'		'
Regulatory Assets	26,211	[1],[3]	16,775	[1],[3]	17,925	[1],[3]
Deferred gas cost adjustments and natural gas price derivatives	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P7Y		'		'
Regulatory Assets	49,870	[1],[3]	12,366	[1],[3]	16,845	[1],[3]
Allowance for funds used during construction	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P45Y		'		'
Regulatory Assets	12,411	[4]	12,315	[4]	12,398	[4]
Employee benefit plans	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P13Y		'		'
Regulatory Assets	64,908	[2]	67,059	[2]	114,386	[2]
Environmental	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'subject to approval		'		'
Regulatory Assets	1,314	[1]	1,800	[1]	1,800	[1]
Asset retirement obligations	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P44Y		'		'
Regulatory Assets	3,282	[1]	3,266	[1]	3,262	[1]
Bond issue cost	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P24Y		'		'
Regulatory Assets	3,311	[1]	3,419	[1]	3,454	[1]
Renewable energy standard adjustment	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P5Y		'		'
Regulatory Assets	12,007	[1]	14,186	[1]	14,936	[1]
Flow through accounting	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P35Y		'		'
Regulatory Assets	25,157	[2]	20,916	[2]	19,222	[2]
Other regulatory assets	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P15Y		'		'
Regulatory Assets	$10,395	[1]	$10,546	[1]	$9,099	[1]
[1]	Recovery of costs, but we are not allowed a rate of return.
[2]	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, respectively.
[3]	Our deferred energy, fuel cost, and gas cost adjustments represent the cost of electricity and gas delivered to our electric and gas utility customers that is either higher or lower than current rates and will be recovered or refunded in future rates. Increases in the current year balances as of September 30, 2014 are primarily due to higher natural gas prices driven by demand and market conditions during our peak winter heating season. Our electric and gas utilities file periodic quarterly, semi-annual, and/or annual filings to recover these costs based on the respective cost mechanisms approved by their applicable state utility commissions.
[4]	In addition to recovery of costs, we are allowed a rate of return.

Materials_Supplies_and_Fuel_De

Materials, Supplies and Fuel (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Inventory, Net [Abstract]	'	'	'
Materials and supplies	$52,682	$50,196	$50,564
Fuel - Electric Utilities	7,108	6,213	6,384
Natural gas in storage held for distribution	45,936	32,069	38,282
Total materials, supplies and fuel	$105,726	$88,478	$95,230

Basic_to_Dilutive_EPS_Details

Basic to Dilutive EPS (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'	'
Net income (loss) available for common stock	$26,836	$23,124	$94,774	$96,839
Weighted average shares - basic	44,415	44,201	44,382	44,143
Dilutive Effect on Basic Earnings Per Share [Abstract]	'	'	'	'
Equity compensation, shares	193	256	202	252
Weighted average shares - diluted	44,608	44,457	44,584	44,395

Earnings_Per_Share_Antidilutiv

Earnings Per Share Anti-dilutive shares (Details)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Shares	99	0	75	9
Equity compensation [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Shares	99	0	75	9

Notes_Payable_Details

Notes Payable (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Balance Outstanding	$184,000,000	$82,500,000	$138,300,000
Revolving Credit Facility [Member]	'	'	'
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Balance Outstanding	184,000,000	82,500,000	138,300,000
Revolving Credit Facility - Letters of Credit Outstanding	31,726,000	22,100,000	53,137,000
Revolving Credit Facility - Current Borrowing Capacity	500,000,000	'	'
Revolving Credit Facility - Expiration Date	29-May-19	'	'
Revolving Credit Facility - Maximum Borrowing Capacity	$750,000,000	'	'
Revolving Credit Facility - Unused Capacity, Commitment Fee Percentage	0.18%	'	'
Revolving Credit Facility - Commitment Fee Percentage Decrease	0.03%	'	'
Debt Disclosure [Abstract]	'	'	'
Recourse Leverage Ratio	54.00%	'	'
Recourse Leverage Ratio, Maximum Allowed, Covenant	65.00%	'	'
Revolving Credit Facility [Member] | Base Rate [Member]	'	'	'
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Interest Rate at Period End	0.13%	'	'
Debt Instrument Interest Rate Increase Decrease Parenthetical Disclosures [Abstract]	'	'	'
Revolving Credit Facility - Interest Rate Decrease	0.25%	'	'
Revolving Credit Facility [Member] | Eurodollar [Member]	'	'	'
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Interest Rate at Period End	1.13%	'	'
Debt Instrument Interest Rate Increase Decrease Parenthetical Disclosures [Abstract]	'	'	'
Revolving Credit Facility - Interest Rate Decrease	0.25%	'	'
Revolving Credit Facility [Member] | Letter of Credit [Member]	'	'	'
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Interest Rate at Period End	1.13%	'	'
Debt Instrument Interest Rate Increase Decrease Parenthetical Disclosures [Abstract]	'	'	'
Revolving Credit Facility - Interest Rate Decrease	0.25%	'	'

Current_Maturities_of_LongTerm

Current Maturities of Long-Term Debt (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'	'
Current maturities of long-term debt	$275,000	$0	$255,694
Black Hills Corporation [Member] | Corporate Term Loan Due June 2015	'	'	'
Debt Instrument [Line Items]	'	'	'
Current maturities of long-term debt	$275,000	'	'

Risk_Management_Activities_Det

Risk Management Activities (Details) (USD $)	9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Derivative [Line Items]	'		'		'
Credit Exposure, Non-Investment Grade Company	$500,000		'		'
Derivative assets, current	0		126,000		717,000
Derivative assets, non-current	0		0		0
Derivative liabilities, current	3,397,000		65,944,000		3,474,000
Derivative liabilities, non-current	3,273,000		11,388,000		5,614,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative liabilities, current	3,397,000		7,039,000		3,474,000
Derivative liabilities, non-current	3,273,000		11,388,000		5,614,000
Derivative, Notional Amount	75,000,000	[1]	150,000,000	[2]	75,000,000	[1]
Weighted Average Fixed Interest Rate	4.97%		5.04%		4.97%
Derivative, Remaining Maturity	'2 years 3 months		'3 years 3 months		'3 years
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	-3,400,000		'		'
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative liabilities, current	'		58,755,000		'
Derivative liabilities, non-current	'		0		'
Derivative, Notional Amount	'		250,000,000	[3]	'
Weighted Average Fixed Interest Rate	'		5.67%		'
Derivative, Remaining Maturity	'		'0 years 3 months		'
Oil and Gas [Member]	'		'		'
Derivative [Line Items]	'		'		'
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	700,000		'		'
Power Generation [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Notional Amount	'		75,000,000		'
Natural Gas, Distribution [Member] | Utilities Group [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative assets, current	0		0		662,000
Derivative assets, non-current	0		0		0
Derivative liabilities, non-current	0		0		0
Net Unrealized (Gain) Loss Included in Regulatory assets or Regulatory liabilities	7,470,000		10,652,000		7,567,000
Natural Gas, Distribution [Member] | Utilities Group [Member] | Future [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	16,290,000		14,010,000		17,930,000
Derivative, Remaining Maturity	'74 months	[4]	'74 months	[4]	'84 months	[4]
Natural Gas, Distribution [Member] | Utilities Group [Member] | Commodity Option [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	7,070,000		6,810,000		3,890,000
Derivative, Remaining Maturity	'6 months	[4]	'6 months	[4]	'8 months	[4]
Natural Gas, Distribution [Member] | Utilities Group [Member] | Basis Swap [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	12,025,000		9,790,000		14,785,000
Derivative, Remaining Maturity	'63 months	[4]	'63 months	[4]	'60 months	[4]
Crude Oil [Member] | Oil and Gas [Member] | Swaps and Options [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	391,500	[5]	499,500	[5]	412,500	[5]
Maximum terms in months - Hedged in Cash Flow Hedge	'1 month	[6]	'3 months	[6]	'3 months	[6]
Derivative assets, current	0		13,000		55,000
Derivative assets, non-current	0		0		0
Derivative liabilities, current	0		98,000		0
Derivative liabilities, non-current	0		0		0
Natural Gas [Member] | Oil and Gas [Member] | Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	7,930,000	[5]	9,874,000	[5]	7,082,500	[5]
Maximum terms in months - Hedged in Cash Flow Hedge	'1 month	[6]	'1 month	[6]	'1 month	[6]
Derivative assets, current	0		113,000		0
Derivative assets, non-current	0		0		0
Derivative liabilities, current	0		52,000		0
Derivative liabilities, non-current	0		0		0
Corporate[Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Notional Amount	'		$75,000,000		'
[1]	These swaps are designated to borrowings on our Revolving Credit Facility, and are priced using three-month LIBOR, matching the floating portion of the related debt.
[2]	At September 30, 2013, $75 million of these interest rate swaps was designated to borrowings on our Revolving Credit Facility and $75 million was designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps were priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that was designated to Black Hills Wyoming was settled during the fourth quarter of 2013 upon repayment of the Black Hills Wyoming project financing.
[3]	These swaps were settled during the fourth quarter of 2013.
[4]	Term reflects the maximum forward period hedged.
[5]	Crude oil in Bbls, natural gas in MMBtus.
[6]	Refers to the tenor of the derivative instrument. Assets and liabilities are classified as current/non-current based on the production month hedged and the corresponding settlement of the derivative instrument.

Risk_Management_Activities_Hed

Risk Management Activities Hedging Activities (Details) (Cash Flow Hedging [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	$4,985	($3,047)	($1,653)	$227
Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)	-2,060	-2,012	-5,442	-4,564
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Interest Rate Swap [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	152	-907	-277	141
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0	0
Interest Rate Swap [Member] | Interest Expense [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)	-925	-1,844	-2,745	-5,460
Commodity Contract [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	4,833	-2,140	-1,376	86
Commodity Contract [Member] | Sales Revenue, Goods, Net [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)	-1,135	-168	-2,697	896
Amount of Gain/(Loss) Recognized in Income on Derivative (Ineffective Portion)	$0	$0	$0	$0

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Hierarchy (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Transfers Between Level 1 and Level 2, Description and Policy [Abstract]	'	'	'
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$0	$0	$0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0	0	0
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount	0	0	0
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Assets, Fair Value Disclosure	0	0	0
Liabilities, Fair Value Disclosure	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Crude Oil [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Crude Oil [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Natural Gas [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Natural Gas [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Natural Gas, Distribution [Member] | Utilities Group [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Assets, Fair Value Disclosure	5,896	3,975	4,156
Liabilities, Fair Value Disclosure	16,701	19,948	95,581
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Liabilities	6,670	9,088	83,142
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Crude Oil [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	2
Derivative Liabilities	0	0	142
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Crude Oil [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	322	130	51
Derivative Liabilities	487	1,229	1,318
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Natural Gas [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Natural Gas [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	1,545	815	1,752
Derivative Liabilities	865	531	232
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Natural Gas, Distribution [Member] | Utilities Group [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	4,029	3,030	2,351
Derivative Liabilities	8,679	9,100	10,747
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Assets, Fair Value Disclosure	0	0	0
Liabilities, Fair Value Disclosure	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Crude Oil [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Crude Oil [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Natural Gas, Distribution [Member] | Utilities Group [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Netting [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Assets, Fair Value Disclosure	-5,896	-3,258	-4,030
Liabilities, Fair Value Disclosure	-10,031	-10,860	-18,249
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Interest Rate Swap [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Liabilities	0	0	-5,960
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Crude Oil [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	-77
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Crude Oil [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	-322	-75	-40
Derivative Liabilities	-487	-1,229	-1,284
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Natural Gas [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Natural Gas [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	-1,545	-815	-1,639
Derivative Liabilities	-865	-531	-181
Fair Value, Measurements, Recurring [Member] | Netting [Member] | Natural Gas, Distribution [Member] | Utilities Group [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	-4,029	-2,368	-2,351
Derivative Liabilities	-8,679	-9,100	-10,747
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Assets, Fair Value Disclosure	0	717	126
Liabilities, Fair Value Disclosure	6,670	9,088	77,332
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Liabilities	6,670	9,088	77,182
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Crude Oil [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	2
Derivative Liabilities	0	0	65
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Crude Oil [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	55	11
Derivative Liabilities	0	0	34
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Natural Gas [Member] | Commodity Option [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	0
Derivative Liabilities	0	0	0
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Natural Gas [Member] | Basis Swap [Member] | Oil and Gas [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	0	113
Derivative Liabilities	0	0	51
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Natural Gas, Distribution [Member] | Utilities Group [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Derivative Assets	0	662	0
Derivative Liabilities	$0	$0	$0

Fair_Value_Measurements_Balanc

Fair Value Measurements - Balance Sheet Location (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified
Designated as Hedging Instrument [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Net	$1,866	$946	$1,805
Derivative Liability, Fair Value, Net	8,023	10,848	20,119
Not Designated as Hedging Instrument [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Net	0	662	0
Derivative Liability, Fair Value, Net	4,650	6,732	73,111
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Derivative Assets, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	1,174	248	846
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Derivative Assets, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	692	698	959
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Derivative Liabilities, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	497	1,541	1,317
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Derivative Liabilities, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	856	219	375
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivative Assets, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	0	662	0
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivative Assets, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	0	0	0
Derivative Asset, Fair Value, Gross Liability	0	0	0
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivative Liabilities, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	48	0	1,795
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivative Liabilities, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	4,602	6,732	6,601
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Derivative Liabilities, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	3,397	3,474	7,039
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Derivative Liabilities, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	0	0	0
Derivative Liability, Fair Value, Gross Liability	3,273	5,614	11,388
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Derivative Liabilities, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	'	'	0
Derivative Liability, Fair Value, Gross Liability	'	'	64,715
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Derivative Liabilities, Non-current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Liability, Fair Value, Gross Asset	'	'	0
Derivative Liability, Fair Value, Gross Liability	'	'	$0

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and cash equivalents	$11,939		$7,841		$13,637
Restricted cash and equivalents	1,918		2		6,782
Notes payable	184,000		82,500		138,300
Carrying Amount [Member]	'		'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and cash equivalents	11,939		7,841		13,637
Restricted cash and equivalents	1,918		2		6,782
Notes payable	184,000		82,500		138,300
Long-term debt, including current maturities	1,382,519		1,396,948		1,211,673
Fair Value [Member]	'		'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and cash equivalents, Fair Value	11,939	[1]	7,841	[1]	13,637	[1]
Restricted cash and equivalents, Fair Value	1,918	[1]	2	[1]	6,782	[1]
Notes payable, Fair Value	184,000	[1]	82,500	[1]	138,300	[1]
Long-term debt, including current maturities, Fair Value	$1,547,359	[2]	$1,491,422	[2]	$1,325,729	[2]
[1]	Carrying value approximates fair value due to either the short-term length of maturity or variable interest rates that approximate prevailing market rates, and therefore is classified in Level 1 in the fair value hierarchy.
[2]	Long-term debt is valued based on observable inputs available either directly or indirectly for similar liabilities in active markets and therefore is classified in Level 2 in the fair value hierarchy.

Other_Comprehensive_Income_Los2

Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Interest expense	$17,919	$23,840	$53,665	$70,881
Revenue	272,087	259,907	1,015,493	920,404
Utilities - Operating and Maintenance	64,245	66,061	201,546	196,728
Non-regulated energy operations and maintenance	20,170	20,484	63,852	62,703
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	38,168	36,458	142,124	147,452
Income tax benefit (expense)	-11,332	-13,334	-47,349	-50,527
Cash Flow Hedging [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	2,060	2,012	5,442	4,564
Income tax benefit (expense)	-732	-586	-1,931	-1,469
Net income (loss) available for common stock	1,328	1,426	3,511	3,095
Cash Flow Hedging [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Interest Rate Contract [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Interest expense	925	1,844	2,745	5,460
Cash Flow Hedging [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Commodity Contract [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Revenue	1,135	168	2,697	-896
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Utilities - Operating and Maintenance	-26	-31	-77	-93
Non-regulated energy operations and maintenance	-22	-32	-93	-96
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Utilities - Operating and Maintenance	158	425	473	1,267
Non-regulated energy operations and maintenance	88	275	274	823
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	198	637	577	1,901
Income tax benefit (expense)	-69	-220	-202	-663
Net income (loss) available for common stock	$129	$417	$375	$1,238

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended						9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax	($14,839)	($19,441)	($18,589)	($31,021)	($30,781)	($36,224)	($14,839)	($31,021)	($17,422)	($35,488)
Other Comprehensive Income (Loss), Net of Tax	4,602	-852	-1,167	-240	5,443	-736	2,583	4,467	'	'
Derivatives Designated as Cash Flow Hedges [Member]	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-4,694	-9,167	-8,611	-12,484	-11,827	-16,906	-4,694	-12,484	-7,133	-15,713
Other Comprehensive Income (Loss), Net of Tax	4,473	-556	-1,478	-657	5,079	-1,193	'	'	'	'
Employee Benefit Plans [Member]	'	'	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-10,145	-10,274	-9,978	-18,537	-18,954	-19,318	-10,145	-18,537	-10,289	-19,775
Other Comprehensive Income (Loss), Net of Tax	$129	($296)	$311	$417	$364	$457	'	'	'	'

Supplemental_Disclosure_of_Cas2

Supplemental Disclosure of Cash Flow Information (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Non-cash Investing and Financing Activities from Continuing Operations [Abstract]	'	'
Property, plant and equipment acquired wtih accrued liabilities	$52,484	$47,214
Increase (decrease) in capitalized assets associated with asset retirement obligations	-2,785	0
Cash (paid) refunded during the period for continuing operations [Abstract]	'	'
Interest (net of amounts capitalized)	-46,086	-57,175
Income taxes, net	($396)	($4,924)

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Pension Plans	'	'	'	'
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'
Service cost	$1,362	$1,608	$4,086	$4,824
Interest cost	3,963	3,825	11,889	11,475
Expected return on plan assets	-4,516	-4,654	-13,549	-13,962
Prior service cost (benefit)	16	16	47	48
Net loss (gain)	1,201	3,062	3,604	9,186
Net periodic benefit cost	2,026	3,857	6,077	11,571
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	10,200	'	10,200	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	0	'
Estimated Future Employer Contributions in Next Fiscal Year	'	'	12,500	'
Non-pension Defined Benefit Postretirement Healthcare Plans	'	'	'	'
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'
Service cost	425	419	1,275	1,257
Interest cost	480	417	1,439	1,251
Expected return on plan assets	-21	-20	-64	-60
Prior service cost (benefit)	-107	-125	-321	-375
Net loss (gain)	40	121	120	363
Net periodic benefit cost	817	812	2,449	2,436
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	956	'	2,868	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	956	'
Estimated Future Employer Contributions in Next Fiscal Year	'	'	3,822	'
Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	'	'	'	'
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'
Service cost	374	348	1,123	1,044
Interest cost	362	332	1,085	996
Prior service cost (benefit)	1	1	2	3
Net loss (gain)	124	198	373	594
Net periodic benefit cost	861	879	2,583	2,637
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	373	'	1,118	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	373	'
Estimated Future Employer Contributions in Next Fiscal Year	'	'	$1,494	'

Commitments_and_Contingencies_

Commitments and Contingencies - Reimbursement Agreement (Details) (Electric Utilities [Member], USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Industrial Development Revenue Bonds Due 2027 [Member]	'
Debt Instrument, Maturity Date	1-Mar-27
Industrial Development Revenue Bonds Due 2021 [Member]	'
Debt Instrument, Maturity Date	1-Sep-21
Surety Bond [Member] | Industrial Development Revenue Bonds Due 2027 [Member]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	10,000
Surety Bond [Member] | Industrial Development Revenue Bonds Due 2021 [Member]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	7,000

Commitments_and_Contingencies_1

Commitments and Contingencies - Other Commitments (Details) (Cheyenne Prairie [Member], USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Cheyenne Prairie [Member]	'
Long-term Purchase Commitment [Line Items]	'
Long-term Purchase Commitment, Amount	$222
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year	$2.50

Commitments_and_Contingencies_2

Commitments and Contingencies - Oil Creek Fire (Details) (Oil Creek Fire [Member], Loss from Catastrophes [Member], USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Minimum [Member]	'
Loss Contingencies [Line Items]	'
Insurance Coverage Deductible Per Occurrence	$1
Maximum [Member]	'
Loss Contingencies [Line Items]	'
Loss Contingency, Damages Sought, Value	$50

Commitments_and_Contingencies_3

Commitments and Contingencies - Dividend Restrictions (Details) (Utilities Group [Member], USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Utilities Group [Member]	'
Related Party Transaction [Line Items]	'
Restricted Net Assets for Subsidiaries	$73

Commitments_and_Contingencies_4

Commitments and Contingencies Commitments and Contingencies - Natural Gas Delivery Agreement (Details) (Oil and Gas [Member])	9 Months Ended
	Sep. 30, 2014
	Mcfe
Oil and Gas [Member]	'
Oil and Gas Delivery Commitments and Contracts, Daily Production	20,000

Guarantees_Details

Guarantees (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Coal Mining [Member] | Indemnification for subsidiary reclamation/surety bonds	'
Statement [Line Items]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	$63,900	[1]
Gas Utilities [Member] | Payment Guarantee [Member]	'
Statement [Line Items]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	$70,000
[1]	We have guarantees in place for reclamation and surety bonds for our subsidiaries. The guarantees were entered into in the normal course of business. To the extent liabilities are incurred as a result of activities covered by the surety bonds, such liabilities are included in our Condensed Consolidated Balance Sheets.

Sale_of_Operating_Asset_Detail

Sale of Operating Asset (Details) (CTII Natural Gas-Fred Generating Unit [Member], Power Generation [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Sep. 03, 2014	Sep. 30, 2014
CTII Natural Gas-Fred Generating Unit [Member] | Power Generation [Member]	'	'
Proceeds from Sale of Property, Plant, and Equipment	$22	'
Deferred Gain on Sale of Property	'	$4.90

Subsequent_Event_Details

Subsequent Event (Details) (Electric Utilities [Member], USD $)	9 Months Ended		0 Months Ended		0 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Oct. 01, 2014	Oct. 01, 2014	Oct. 01, 2014	Oct. 01, 2014	Oct. 01, 2014
	Polution Control Revenue Bonds Due 2024 [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
		First Mortgage Bonds Due 2044 [Member]	Black Hills Power [Member]	Black Hills Power [Member]	Cheyenne Light [Member]	Cheyenne Light [Member]
			First Mortgage Bonds Due 2044 [Member]	First Mortgage Bonds Due 2044 [Member]	First Mortgage Bonds Due 2044 [Member]	First Mortgage Bonds Due 2044 [Member]
Long-term Debt, Gross	'	$160	'	$85	'	$75
Debt Instrument, Interest Rate, Stated Percentage	5.35%	'	'	4.43%	'	4.53%
Debt Instrument, Maturity Date	'	'	20-Oct-44	'	20-Oct-44	'
Extinguishment of Debt, Amount	$12	'	'	'	'	'