Black Hills (BKH) 10-Q 6 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	6 Months Ended
	Jun. 30, 2014	Jul. 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-Jun-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	44,641,421
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'

Condensed_Statements_of_Income

Condensed Statements of Income (unaudited) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue	$283,237	$279,826	$743,406	$660,497
Utilities -	'	'	'	'
Fuel, purchased power and cost of natural gas sold	101,331	99,172	331,799	267,345
Operations and maintenance	66,074	64,977	137,301	130,667
Non-regulated energy operations and maintenance	21,350	20,890	43,682	42,219
Depreciation, depletion and amortization	36,712	35,152	72,795	69,933
Taxes - property, production and severance	11,044	10,069	21,380	20,449
Other operating expenses	149	529	274	1,001
Total operating expenses	236,660	230,789	607,231	531,614
Operating income	46,577	49,037	136,175	128,883
Interest charges -	'	'	'	'
Interest expense incurred (including amortization of debt issuance costs, premiums and discounts and realized settlements on interest rate swaps)	-17,886	-23,369	-35,746	-47,041
Allowance for funds used during construction - borrowed	256	411	526	484
Capitalized interest	246	272	503	538
Unrealized gain (loss) on interest rate swaps, net	0	18,793	0	26,249
Interest income	576	475	966	760
Allowance for funds used during construction - equity	293	42	531	242
Other income (expense), net	409	473	1,000	879
Total other income (expense), net	-16,106	-2,903	-32,220	-17,889
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	30,471	46,134	103,955	110,994
Equity in earnings (loss) of unconsolidated subsidiaries	0	0	0	-86
Income tax benefit (expense)	-10,651	-15,616	-36,017	-37,193
Net income (loss) available for common stock	$19,820	$30,518	$67,938	$73,715
Earnings (loss) per share, Basic -	'	'	'	'
Total income (loss) per share, Basic	$0.45	$0.69	$1.53	$1.67
Earnings (loss) per share, Diluted -	'	'	'	'
Total income (loss) per share, Diluted	$0.44	$0.69	$1.52	$1.66
Weighted Average Number of Shares Outstanding:	'	'	'	'
Basic	44,399	44,172	44,365	44,113
Diluted	44,588	44,412	44,571	44,363
Dividends paid per share of common stock	$0.39	$0.38	$0.78	$0.76

Condensed_Consolidated_Stateme

Condensed Consolidated Statement of Comprehensive Income (unaudited) Statement (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income (loss) available for common stock	$19,820	$30,518	$67,938	$73,715
Other comprehensive income (loss), net of tax:	'	'	'	'
Fair value adjustments on derivatives designated as cash flow hedges (net of tax (expense) benefit of $1,115 and $(2,174) for the three months ended 2014 and 2013 and $2,422 and $(1,057) for the six months ended 2014 and 2013, respectively)	-1,959	3,878	-4,216	2,217
Reclassification adjustments for cash flow hedges settled and included in net income (loss) (net of tax (expense) benefit of $(774) and $(647) for the three months ended 2014 and 2013 and $(1,199) and $(883) for the six months ended 2014 and 2013, respectively)	1,403	1,201	2,183	1,669
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 six months ended 2014 and 2013, respectively)	0	0	-2	0
Benefit plan liability tax adjustments - net gain (loss)	-394	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 six months ended 2014 and 2013, respectively)	0	0	164	0
Reclassification adjustments of benefit plan liability - prior service cost (net of tax of $39 and $(268) for the three months ended 2014 and 2013 and $43 and $(251) for the six months ended 2014 and 2013, respectively)	-70	364	-79	318
Reclassification adjustments of benefit plan liability - net gain (loss) (net of tax of $(91) and $0 for the three months ended 2014 and 2013 and $(176) and $(192) for the six months ended 2014 and 2013, respectively)	168	0	325	503
Other comprehensive income (loss), net of tax	-852	5,443	-2,019	4,707
Comprehensive income (loss) available for common stock	18,968	35,961	65,919	78,422
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures	'	'	'	'
Fair value adjustment on derivatives designated as cash flow hedges, (tax) benefit	1,115	-2,174	2,422	-1,057
Reclassification adjustments of cash flow hedges settled and included in net income, (tax) benefit	-774	-647	-1,199	-883
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	39	-268	43	-251
Reclassification adjustment of benefit plan liabilities actuarial gain (loss), (tax) benefit	($91)	$0	($176)	($192)

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (unaudited) Statement (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Current assets:	'	'	'
Cash and cash equivalents	$14,697	$7,841	$30,633
Restricted cash and equivalents	2	2	7,279
Accounts receivable, net	135,145	177,573	132,726
Materials, supplies and fuel	81,164	88,478	73,768
Derivative assets, current	1,737	717	903
Income tax receivable, net	1,043	1,460	146
Deferred income tax assets, net, current	23,872	18,889	38,764
Regulatory assets, current	64,735	24,451	26,258
Other current assets	21,660	25,877	27,595
Total current assets	344,055	345,288	338,072
Investments	17,096	16,697	16,566
Property, plant and equipment	4,408,291	4,259,445	4,066,502
Less accumulated depreciation and depletion	-1,325,660	-1,269,148	-1,234,578
Total property, plant and equipment, net	3,082,631	2,990,297	2,831,924
Other assets:	'	'	'
Goodwill	353,396	353,396	353,396
Intangible assets, net	3,286	3,397	3,508
Regulatory assets, non-current	138,226	138,197	180,646
Other assets, non-current	31,808	27,906	22,402
Total other assets, non-current	526,716	522,896	559,952
TOTAL ASSETS	3,970,498	3,875,178	3,746,514
Current liabilities:	'	'	'
Accounts payable	100,098	130,416	88,071
Accrued liabilities	141,177	151,277	135,819
Derivative liabilities, current	3,480	3,474	69,270
Regulatory liabilities, current	828	10,727	20,550
Notes payable	132,700	82,500	100,000
Current maturities of long-term debt	275,000	0	255,507
Total current liabilities	653,283	378,394	669,217
Long-term debt, net of current maturities	1,121,950	1,396,948	958,559
Deferred credits and other liabilities:	'	'	'
Deferred income tax liabilities, net, non-current	476,059	432,287	387,674
Derivative liabilities, non-current	4,251	5,614	12,384
Regulatory liabilities, non-current	119,462	109,429	129,013
Benefit plan liabilities	116,403	111,479	177,216
Other deferred credits and other liabilities	137,765	133,279	129,763
Total deferred credits and other liabilities	853,940	792,088	836,050
Commitments and contingencies (See Notes 7, 8, 13, 14 and 15)	'	'	'
Stockholders’ equity:	'	'	'
Common stock $1 par value; 100,000,000 shares authorized; issued 44,682,885; 44,550,239; and 44,516,472 shares, respectively	44,683	44,550	44,517
Additional paid-in capital	744,505	742,344	737,729
Retained earnings	573,379	540,244	532,810
Treasury stock, at cost – 40,951; 50,877; and 42,480 shares, respectively	-1,801	-1,968	-1,587
Accumulated other comprehensive income (loss)	-19,441	-17,422	-30,781
Total stockholders’ equity	1,341,325	1,307,748	1,282,688
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$3,970,498	$3,875,178	$3,746,514

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (unaudited) Parantheticals (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Common Stock, Par Per Share	$1	$1	$1
Common Stock, Shares, Issued	44,682,885	44,550,239	44,516,472
Treasury Stock, Shares	40,951	50,877	42,480
Common Stock, Shares Authorized	100,000,000	100,000,000	100,000,000
Common Stock, Shares, Outstanding	44,641,934	44,499,362	44,473,992

Condensed_Consoldiated_Stateme

Condensed Consoldiated Statement of Cash Flows (unaudited) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Operating activities:	'	'
Net income (loss) available for common stock	$67,938	$73,715
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	72,795	69,933
Deferred financing cost amortization	1,107	2,188
Derivative fair value adjustments	-1,660	4,248
Stock compensation	6,908	6,896
Unrealized (gain) loss on interest rate swaps, net	0	-26,249
Deferred income taxes	35,514	36,607
Employee benefit plans	7,409	11,096
Other adjustments, net	1,481	8,967
Changes in certain operating assets and liabilities:	'	'
Materials, supplies and fuel	7,314	8,940
Accounts receivable, unbilled revenue and other operating assets	-5,851	28,377
Accounts payable and other current liabilities	-24,978	-26,739
Other operating activities, net	5,858	-594
Net cash provided by (used in) operating activities	173,835	197,385
Investing activities:	'	'
Property, plant and equipment additions	-177,302	-147,230
Other investing activities	-2,994	2,006
Net cash provided by (used in) investing activities	-180,296	-145,224
Financing activities:	'	'
Dividends paid on common stock	-34,803	-33,774
Common stock issued	1,693	2,570
Short-term borrowings - issuances	214,100	133,300
Short-term borrowings - repayments	-163,900	-310,300
Long-term debt - issuances	0	275,000
Long-term debt - repayments	0	-103,786
Other financing activities	-3,773	0
Net cash provided by (used in) financing activities	13,317	-36,990
Net change in cash and cash equivalents	6,856	15,171
Cash and Cash Equivalents:	'	'
Cash and cash equivalents, beginning of period	7,841	15,462
Cash and cash equivalents, end of period	$14,697	$30,633

Managements_Statement

Management's Statement	6 Months Ended
	Jun. 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 June 30, 2014, December 31, 2013, and June 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 six months ended June 30, 2014 and June 30, 2013, and our financial condition as of June 30, 2014, December 31, 2013, and June 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	6 Months Ended
	Jun. 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 June 30, 2014		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	158,740		$	3,144			$	11,427
	Gas		102,499			—				1,994
	Non-regulated Energy:
	Power Generation		1,267			20,713				7,194
	Coal Mining		5,583			9,068				2,016
	Oil and Gas		15,148			—				(1,660		)
	Corporate activities		—			—				(1,151		)
	Inter-company eliminations		—			(32,925		)		—
	Total		$	283,237		$	—			$	19,820
	Three Months Ended June 30, 2013		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	154,338		$	3,694			$	10,610
	Gas		105,836			—				3,192
	Non-regulated Energy:
	Power Generation		1,031			19,094				5,031
	Coal Mining		6,807			7,511				1,973
	Oil and Gas		11,814			—				(1,964		)
	Corporate activities (a)		—			—				11,679
	Inter-company eliminations		—			(30,299		)		(3		)
	Total		$	279,826		$	—			$	30,518
	Six Months Ended June 30, 2014		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	336,835		$	7,151			$	26,002
	Gas		361,836			—				26,692
	Non-regulated Energy:
	Power Generation		2,536			41,792				15,267
	Coal Mining		12,201			17,948				4,480
	Oil and Gas		29,998			—				(3,682		)
	Corporate activities		—			—				(821		)
	Inter-company eliminations		—			(66,891		)		—
	Total		$	743,406		$	—			$	67,938
	Six Months Ended June 30, 2013		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	312,821		$	7,841			$	22,966
	Gas		305,648			—				21,675
	Non-regulated Energy:
	Power Generation		2,053			38,432				10,675
	Coal Mining		12,817			15,084				3,038
	Oil and Gas		27,158			—				(2,017		)
	Corporate activities (a)		—			—				17,378
	Inter-company eliminations		—			(61,357		)		—
	Total		$	660,497		$	—			$	73,715
	__________
	(a)	Corporate activities include a $12 million and a $17 million after-tax non-cash mark-to-market gain for the three and six months ended June 30, 2013, respectively on certain interest rate swaps.
	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-Jun-14			31-Dec-13				30-Jun-13
	Utilities:
	Electric (a)	$	2,603,900		$	2,525,947			$	2,417,952
	Gas	799,365			805,617				734,337
	Non-regulated Energy:
	Power Generation (a)	85,269			95,692				108,515
Coal Mining	73,701			78,825				82,553
Oil and Gas	307,837			288,366				256,855
Corporate activities	100,426			80,731				146,302
Total assets	$	3,970,498		$	3,875,178			$	3,746,514
__________
(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	6 Months Ended
	Jun. 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-Jun-14	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	48,333	$	21,716	$	(622	)	$	69,427
	Gas Utilities	43,104		9,265		(1,027		)	51,342
	Power Generation	1,388		—		—			1,388
	Coal Mining	1,866		—		—			1,866
	Oil and Gas	9,123		—		(13		)	9,110
	Corporate	2,012		—		—			2,012
	Total	$	105,826	$	30,981	$	(1,662	)	$	135,145
		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-Jun-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	45,250	$	24,290	$	(630	)	$	68,910
	Gas Utilities	38,749		13,192		(1,074		)	50,867
	Power Generation	157		—		—			157
	Coal Mining	2,503		—		—			2,503
	Oil and Gas	8,373		—		(19		)	8,354
	Corporate	1,935		—		—			1,935
	Total	$	96,967	$	37,482	$	(1,723	)	$	132,726

Regulatory_Accounting

Regulatory Accounting	6 Months Ended
	Jun. 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-Jun-14		31-Dec-13		30-Jun-13
	Regulatory assets
	Deferred energy and fuel cost adjustments - current (a)(d)	1	$	29,605	$	16,775	$	15,951
	Deferred gas cost adjustments and natural gas price derivatives (a)(d)	7	39,040		12,366		13,090
	AFUDC (b)	45	12,468		12,315		12,456
	Employee benefit plans (c)	13	65,874		67,059		115,379
	Environmental (a)	subject to approval	1,314		1,800		1,798
	Asset retirement obligations (a)	44	3,278		3,266		3,257
	Bond issue cost (a)	24	3,347		3,419		3,489
	Renewable energy standard adjustment (a)	5	14,501		14,186		14,694
	Flow through accounting (c)	35	22,754		20,916		17,995
	Other regulatory assets (a)	15	10,780		10,546		8,795
			$	202,961	$	162,648	$	206,904
	Regulatory liabilities
	Deferred energy and gas costs (a)	1	$	6,490	$	11,708	$	22,340
	Employee benefit plans (c)	13	34,356		34,431		60,214
	Cost of removal (a)	44	70,841		64,970		59,461
	Other regulatory liabilities (c)	25	8,603		9,047		7,548
			$	120,290	$	120,156	$	149,563
	__________
	(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 June 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	6 Months Ended
	Jun. 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-Jun-14		31-Dec-13		30-Jun-13
	Materials and supplies	$	51,925	$	50,196	$	51,334
	Fuel - Electric Utilities	7,679		6,213		6,817
	Natural gas in storage held for distribution	21,560		32,069		15,617
	Total materials, supplies and fuel	$	81,164	$	88,478	$	73,768

Earnings_Per_Share

Earnings Per Share	6 Months Ended
	Jun. 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 June 30,						Six Months Ended June 30,
		2014			2013			2014		2013
	Net income (loss) available for common stock	$	19,820		$	30,518		$	67,938	$	73,715
	Weighted average shares - basic	44,399			44,172			44,365		44,113
	Dilutive effect of:
	Equity compensation	189			240			206		250
	Weighted average shares - diluted	44,588			44,412			44,571		44,363
	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 June 30,					Six Months Ended June 30,
		2014		2013			2014	2013
	Equity compensation	81		28			63	34
	Anti-dilutive shares	81		28			63	34

Notes_Payable_and_Current_Matu

Notes Payable and Current Maturities of Long-term Debt

6 Months Ended

Jun. 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-Jun-14

31-Dec-13

30-Jun-13

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Revolving Credit Facility

$

132,700

$

20,272

$

82,500

$

22,100

$

100,000

$

43,157

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 June 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 June 30, 2014, our Corporate term loan due June 19, 2015, for $275 million has been re-classified to Current maturities of long-term debt from Long-term debt, net of current maturities.

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 June 30, 2014

Covenant Requirement

Recourse Leverage Ratio

54%

Less than

65%

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

Risk_Management_Activities_Not

Risk Management Activities (Notes)	6 Months Ended
	Jun. 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 June 30, 2014, our credit exposure included a $0.5 million exposure to a non-investment grade energy marketing company. 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-Jun-14							31-Dec-13							30-Jun-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)	424,500			9,265,000				412,500			7,082,500				520,500		10,712,500
	Maximum terms in months (b)	1			1				3			1				6		1
	Derivative assets, current	$	—		$	—			$	55		$	—			$	610	$	293
	Derivative assets, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	Derivative liabilities, current	$	—		$	—			$	—		$	—			$	130	$	276
	Derivative liabilities, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	__________
	(a)	Crude oil in Bbls, natural gas in MMBtus.
	(b)	Refers to the term of the derivative instrument. Assets and liabilities are classified as current/non-current based on the term of the hedged transaction and the corresponding settlement of the derivative instrument.
	A $3.4 million loss is included in AOCI at June 30, 2014, and would be realized over the next 12 months if market prices remained equal to June 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-Jun-14					31-Dec-13					30-Jun-13
		Notional			Maximum		Notional			Maximum		Notional			Maximum
		(MMBtus)			Term		(MMBtus)			Term		(MMBtus)			Term
					(months)					(months)					(months)
	Natural gas futures purchased	16,240,000			78		17,930,000			84		13,330,000			77
	Natural gas options purchased	3,980,000			9		3,890,000			8		2,850,000			5
	Natural gas basis swaps purchased	13,415,000			66		14,785,000			60		10,650,000			66
	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-Jun-14			31-Dec-13			30-Jun-13
	Derivative assets, current	$	1,737		$	662		$	—
	Derivative assets, non-current	$	—		$	—		$	—
	Derivative liabilities, non-current	$	—		$	—		$	—
	Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	3,561		$	7,567		$	8,450
	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-Jun-14				31-Dec-13				30-Jun-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	2.5				3				3.5			0.5
	Derivative liabilities, current	$	3,480			$	3,474			$	6,965		$	61,899
	Derivative liabilities, non-current	$	4,251			$	5,614			$	12,384		$	—
	__________
	(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 June 30, 2013, $75 million of these interest rate swaps were designated to borrowings on our Revolving Credit Facility and $75 million were designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps are priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that were designated to Black Hills Wyoming were 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 June 30, 2014, market interest rates and balances related to our interest rate swaps, a loss of approximately $3.5 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 June 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		$	(337	)		Interest expense		$	(926	)				$	—
Commodity derivatives		(2,737		)		Revenue		(1,251		)				—
Total		$	(3,074	)				$	(2,177	)				$	—
Three Months Ended June 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		$	1,067			Interest expense		$	(1,820	)				$	—
Commodity derivatives		4,985				Revenue		(28		)				—
Total		$	6,052					$	(1,848	)				$	—
Six Months Ended June 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		$	(429	)		Interest expense		$	(1,820	)				$	—
Commodity derivatives		(6,209		)		Revenue		(1,562		)				—
Total		$	(6,638	)				$	(3,382	)				$	—
Six Months Ended June 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		$	1,048			Interest expense		$	(3,616	)				$	—
Commodity derivatives		2,226				Revenue		1,064						—
Total		$	3,274					$	(2,552	)				$	—

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
	Jun. 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 June 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	—			—			—		—			—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			600			—		(600		)	—
	Commodity derivatives — Utilities	—			4,342			—		(2,605		)	1,737
	Total	$	—		$	4,942		$	—	$	(3,205	)	$	1,737
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			4,020			—		(4,020		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			2,030			—		(2,030		)	—
	Commodity derivatives — Utilities	—			5,989			—		(5,989		)	—
	Interest rate swaps	—			7,731			—		—			7,731
	Total	$	—		$	19,770		$	—	$	(12,039	)	$	7,731
		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 June 30, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
Options -- Oil	$	—		$	45		$	—	$	(6	)	$	39
Basis Swaps -- Oil	—			1,109			—		(538		)	571
Options -- Gas	—			—			—		—			—
Basis Swaps -- Gas	—			1,882			—		(1,589		)	293
Commodity derivatives — Utilities	—			1,378			—		(1,378		)	—
Total	$	—		$	4,414		$	—	$	(3,511	)	$	903
Liabilities:
Commodity derivatives — Oil and Gas
Options -- Oil	$	—		$	181		$	—	$	(98	)	$	83
Basis Swaps -- Oil	—			350			—		(303		)	47
Options -- Gas	—			—			—		—			—
Basis Swaps -- Gas	—			445			—		(169		)	276
Commodity derivatives — Utilities	—			8,581			—		(8,581		)	—
Interest rate swaps	—			87,208			—		(5,960		)	81,248
Total	$	—		$	96,765		$	—	$	(15,111	)	$	81,654
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 June 30, 2014, December 31, 2013, and June 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 June 30, 2014
	Balance Sheet Location		Fair Value			Fair Value
			of Asset			of Liability
			Derivatives			Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current		$	262		$	—
Commodity derivatives	Derivative assets — non-current		338			—
Commodity derivatives	Derivative liabilities — current		—			3,702
Commodity derivatives	Derivative liabilities — non-current		—			2,348
Interest rate swaps	Derivative liabilities — current		—			3,480
Interest rate swaps	Derivative liabilities — non-current		—			4,251
Total derivatives designated as hedges			$	600		$	13,781
Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current		$	1,737		$	—
Commodity derivatives	Derivative assets — non-current		—			—
Commodity derivatives	Derivative liabilities — current		—			—
Commodity derivatives	Derivative liabilities — non-current		—			3,384
Total derivatives not designated as hedges			$	1,737		$	3,384
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 June 30, 2013
	Balance Sheet Location		Fair Value			Fair Value
			of Asset			of Liability
			Derivatives			Derivatives
Derivatives designated as hedges:
Commodity derivatives	Derivative assets — current		$	1,225		$	—
Commodity derivatives	Derivative assets — non-current		1,651			—
Commodity derivatives	Derivative liabilities — current		—			889
Commodity derivatives	Derivative liabilities — non-current		—			41
Interest rate swaps	Derivative liabilities — current		—			6,965
Interest rate swaps	Derivative liabilities — non-current		—			12,384
Total derivatives designated as hedges			$	2,876		$	20,279
Derivatives not designated as hedges:
Commodity derivatives	Derivative assets — current		$	160		$	—
Commodity derivatives	Derivative assets — non-current		—			—
Commodity derivatives	Derivative liabilities — current		—			1,884
Commodity derivatives	Derivative liabilities — non-current		—			5,365
Interest rate swaps	Derivative liabilities — current		—			67,859
Interest rate swaps	Derivative liabilities — non-current		—			—
Total derivatives not designated as hedges			$	160		$	75,108

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	6 Months Ended
	Jun. 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-Jun-14				31-Dec-13				30-Jun-13
		Carrying		Fair Value		Carrying		Fair Value		Carrying		Fair Value
		Amount				Amount				Amount
	Cash and cash equivalents (a)	$	14,697	$	14,697	$	7,841	$	7,841	$	30,633	$	30,633
	Restricted cash and equivalents (a)	$	2	$	2	$	2	$	2	$	7,279	$	7,279
	Notes payable (a)	$	132,700	$	132,700	$	82,500	$	82,500	$	100,000	$	100,000
	Long-term debt, including current maturities (b)	$	1,396,950	$	1,578,756	$	1,396,948	$	1,491,422	$	1,214,066	$	1,323,543
	__________
	(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)	6 Months Ended
	Jun. 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						Six Months Ended
			30-Jun-14			30-Jun-13			30-Jun-14			30-Jun-13
	Gains (losses) on cash flow hedges:
	Interest rate swaps	Interest expense	$	926		$	1,820		$	1,820		$	3,616
	Commodity contracts	Revenue	1,251			28			1,562			(1,064		)
			2,177			1,848			3,382			2,552
	Income tax	Income tax benefit (expense)	(774		)	(647		)	(1,199		)	(883		)
	Reclassification adjustments related to cash flow hedges, net of tax		$	1,403		$	1,201		$	2,183		$	1,669
	Amortization of defined benefit plans:
	Prior service cost	Utilities - Operations and maintenance	$	(25	)	$	(31	)	$	(51	)	$	(62	)
		Non-regulated energy operations and maintenance	(84		)	(32		)	(71		)	(64		)
	Actuarial gain (loss)	Utilities - Operations and maintenance	158			421			315			842
		Non-regulated energy operations and maintenance	101			274			186			548
			150			632			379			1,264
	Income tax	Income tax benefit (expense)	(52		)	(268		)	(133		)	(443		)
	Reclassification adjustments related to defined benefit plans, net of tax		$	98		$	364		$	246		$	821
	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	)
	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	)

Supplemental_Disclosure_of_Cas

Supplemental Disclosure of Cash Flow Information	6 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Disclosure of Cash Flow Information [Text Block]	'
	SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
	Six months ended	30-Jun-14			30-Jun-13
		(in thousands)
	Non-cash investing and financing activities from continuing operations—
	Property, plant and equipment acquired with accrued liabilities	$	40,611		$	45,000
	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)	$	(35,009	)	$	(44,191	)
	Income taxes, net	$	(396	)	$	(5,406	)

Employee_Benefit_Plans

Employee Benefit Plans	6 Months Ended
	Jun. 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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	1,362		$	1,608		$	2,724		$	3,216
	Interest cost	3,963			3,825			7,926			7,650
	Expected return on plan assets	(4,516		)	(4,654		)	(9,032		)	(9,308		)
	Prior service cost	16			16			32			32
	Net loss (gain)	1,201			3,062			2,403			6,124
	Net periodic benefit cost	$	2,026		$	3,857		$	4,053		$	7,714
	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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	425		$	419		$	850		$	838
	Interest cost	480			417			959			834
	Expected return on plan assets	(21		)	(20		)	(42		)	(40		)
	Prior service cost (benefit)	(107		)	(125		)	(214		)	(250		)
	Net loss (gain)	40			121			80			242
	Net periodic benefit cost	$	817		$	812		$	1,633		$	1,624
	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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	374		$	348		$	749		$	696
	Interest cost	362			332			724			664
	Prior service cost	1			1			1			2
	Net loss (gain)	124			198			249			396
	Net periodic benefit cost	$	861		$	879		$	1,723		$	1,758
	Contributions
	We anticipate that we will make contributions to the benefit plans during 2014 and 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
		Three Months Ended June 30, 2014			Six Months Ended June 30, 2014			Contributions Anticipated for 2014			Contributions Anticipated for 2015
	Defined Benefit Pension Plans	$	—		$	—		$	—		$	2,806
	Non-pension Defined Benefit Postretirement Healthcare Plans	$	956		$	1,912		$	1,912		$	3,822
	Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	373		$	746		$	746		$	1,494

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 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.
	Bond Purchase Agreements
	On June 30, 2014, Black Hills Power and Cheyenne Light entered into agreements to issue $160 million of first mortgage bonds to finance Cheyenne Prairie. Black Hills Power will issue $85 million of 4.43% coupon first mortgage bonds due October 20, 2044, and Cheyenne Light will issue $75 million of 4.53% coupon first mortgage bonds due October 20, 2044. The closing for the sale of the first mortgage bonds for both utilities is anticipated to be October 1, 2014, subject to satisfaction of customary closing conditions.
	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. We believe that our reserves dedicated to the gathering system, and the projected volumes are adequate to materially satisfy our delivery commitments under this agreement.
	Turbine Sale Agreement
	On May 6, 2013, Black Hills Wyoming entered into an agreement to sell its 40 MW CTII natural-gas fired generating unit to the City of Gillette, Wyoming for approximately $22 million, upon expiration of the PPA with Cheyenne Light in August 2014. As part of the sale, Black Hills Wyoming will provide services to the City of Gillette through an economy energy PPA. The sale received FERC approval on July 14, 2014, and is expected to close by August 31, 2014.
	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 of Cheyenne Prairie, a 132 MW natural gas-fired electric generating facility jointly owned by Cheyenne Light and Black Hills Power is expected to cost approximately $222 million. Construction is expected to be completed by September 30, 2014. As of June 30, 2014, committed contracts for equipment purchases and for construction were 100% and 98% complete, respectively.
	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 June 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 June 30, 2014, we were in compliance with these covenants.
	Due to our holding company structure, substantially all of our operating cash flows are provided by dividends paid or distributions made by our subsidiaries. The cash to pay dividends to our stockholders is derived from these cash flows. As a result, certain statutory limitations or regulatory or financing agreements could affect the levels of distributions allowed to be made by our subsidiaries. The following restrictions on distributions from our subsidiaries existed at June 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 June 30, 2014, the restricted net assets at our Utilities Group were approximately $141 million.

Guarantees

Guarantees	6 Months Ended
	Jun. 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-Jun-14		Expiration
	Indemnification for subsidiary reclamation/surety bonds (1)	$	65,744	Ongoing
	_______________________
	-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.
	During the second quarter, 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.

Business_Segment_Information_T

Business Segment Information (Tables)	6 Months Ended
	Jun. 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 June 30, 2014		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	158,740		$	3,144			$	11,427
	Gas		102,499			—				1,994
	Non-regulated Energy:
	Power Generation		1,267			20,713				7,194
	Coal Mining		5,583			9,068				2,016
	Oil and Gas		15,148			—				(1,660		)
	Corporate activities		—			—				(1,151		)
	Inter-company eliminations		—			(32,925		)		—
	Total		$	283,237		$	—			$	19,820
	Three Months Ended June 30, 2013		External			Inter-company				Net Income (Loss)
			Operating			Operating
			Revenue			Revenue
	Utilities:
	Electric		$	154,338		$	3,694			$	10,610
	Gas		105,836			—				3,192
	Non-regulated Energy:
	Power Generation		1,031			19,094				5,031
	Coal Mining		6,807			7,511				1,973
	Oil and Gas		11,814			—				(1,964		)
	Corporate activities (a)		—			—				11,679
	Inter-company eliminations		—			(30,299		)		(3		)
	Total		$	279,826		$	—			$	30,518
	Six Months Ended June 30, 2014		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	336,835		$	7,151			$	26,002
	Gas		361,836			—				26,692
	Non-regulated Energy:
	Power Generation		2,536			41,792				15,267
	Coal Mining		12,201			17,948				4,480
	Oil and Gas		29,998			—				(3,682		)
	Corporate activities		—			—				(821		)
	Inter-company eliminations		—			(66,891		)		—
	Total		$	743,406		$	—			$	67,938
	Six Months Ended June 30, 2013		External			Intercompany				Net Income (Loss)
			Operating			Operating
			Revenues			Revenues
	Utilities:
	Electric		$	312,821		$	7,841			$	22,966
	Gas		305,648			—				21,675
	Non-regulated Energy:
	Power Generation		2,053			38,432				10,675
	Coal Mining		12,817			15,084				3,038
	Oil and Gas		27,158			—				(2,017		)
	Corporate activities (a)		—			—				17,378
	Inter-company eliminations		—			(61,357		)		—
	Total		$	660,497		$	—			$	73,715
	__________
	(a)	Corporate activities include a $12 million and a $17 million after-tax non-cash mark-to-market gain for the three and six months ended June 30, 2013, respectively on certain interest rate swaps.
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-Jun-14			31-Dec-13				30-Jun-13
	Utilities:
	Electric (a)	$	2,603,900		$	2,525,947			$	2,417,952
	Gas	799,365			805,617				734,337
	Non-regulated Energy:
	Power Generation (a)	85,269			95,692				108,515
	Coal Mining	73,701			78,825				82,553
	Oil and Gas	307,837			288,366				256,855
	Corporate activities	100,426			80,731				146,302
	Total assets	$	3,970,498		$	3,875,178			$	3,746,514
	__________
	(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_R

Accounts Receivable Accounts Receivable (Tables)	6 Months Ended
	Jun. 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-Jun-14	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	48,333	$	21,716	$	(622	)	$	69,427
	Gas Utilities	43,104		9,265		(1,027		)	51,342
	Power Generation	1,388		—		—			1,388
	Coal Mining	1,866		—		—			1,866
	Oil and Gas	9,123		—		(13		)	9,110
	Corporate	2,012		—		—			2,012
	Total	$	105,826	$	30,981	$	(1,662	)	$	135,145
		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-Jun-13	Receivable, Trade		Revenue		Doubtful Accounts			Receivable, net
	Electric Utilities	$	45,250	$	24,290	$	(630	)	$	68,910
	Gas Utilities	38,749		13,192		(1,074		)	50,867
	Power Generation	157		—		—			157
	Coal Mining	2,503		—		—			2,503
	Oil and Gas	8,373		—		(19		)	8,354
	Corporate	1,935		—		—			1,935
	Total	$	96,967	$	37,482	$	(1,723	)	$	132,726

Regulatory_Assets_and_Liabilit

Regulatory Assets and Liabilities (Tables)	6 Months Ended
	Jun. 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-Jun-14		31-Dec-13		30-Jun-13
	Regulatory assets
	Deferred energy and fuel cost adjustments - current (a)(d)	1	$	29,605	$	16,775	$	15,951
	Deferred gas cost adjustments and natural gas price derivatives (a)(d)	7	39,040		12,366		13,090
	AFUDC (b)	45	12,468		12,315		12,456
	Employee benefit plans (c)	13	65,874		67,059		115,379
	Environmental (a)	subject to approval	1,314		1,800		1,798
	Asset retirement obligations (a)	44	3,278		3,266		3,257
	Bond issue cost (a)	24	3,347		3,419		3,489
	Renewable energy standard adjustment (a)	5	14,501		14,186		14,694
	Flow through accounting (c)	35	22,754		20,916		17,995
	Other regulatory assets (a)	15	10,780		10,546		8,795
			$	202,961	$	162,648	$	206,904
	Regulatory liabilities
	Deferred energy and gas costs (a)	1	$	6,490	$	11,708	$	22,340
	Employee benefit plans (c)	13	34,356		34,431		60,214
	Cost of removal (a)	44	70,841		64,970		59,461
	Other regulatory liabilities (c)	25	8,603		9,047		7,548
			$	120,290	$	120,156	$	149,563
	__________
	(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 June 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)	6 Months Ended
	Jun. 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-Jun-14		31-Dec-13		30-Jun-13
	Materials and supplies	$	51,925	$	50,196	$	51,334
	Fuel - Electric Utilities	7,679		6,213		6,817
	Natural gas in storage held for distribution	21,560		32,069		15,617
	Total materials, supplies and fuel	$	81,164	$	88,478	$	73,768

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	6 Months Ended
	Jun. 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 June 30,						Six Months Ended June 30,
		2014			2013			2014		2013
	Net income (loss) available for common stock	$	19,820		$	30,518		$	67,938	$	73,715
	Weighted average shares - basic	44,399			44,172			44,365		44,113
	Dilutive effect of:
	Equity compensation	189			240			206		250
	Weighted average shares - diluted	44,588			44,412			44,571		44,363
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 June 30,					Six Months Ended June 30,
		2014		2013			2014	2013
	Equity compensation	81		28			63	34
	Anti-dilutive shares	81		28			63	34

Notes_Payable_and_Current_Matu1

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

6 Months Ended

Jun. 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-Jun-14

31-Dec-13

30-Jun-13

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Balance Outstanding

Letters of Credit

Revolving Credit Facility

$

132,700

$

20,272

$

82,500

$

22,100

$

100,000

$

43,157

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 June 30, 2014

Covenant Requirement

Recourse Leverage Ratio

54%

Less than

65%

Risk_Management_Activities_Tab

Risk Management Activities (Tables)	6 Months Ended
	Jun. 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-Jun-14				31-Dec-13				30-Jun-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	2.5				3				3.5			0.5
	Derivative liabilities, current	$	3,480			$	3,474			$	6,965		$	61,899
	Derivative liabilities, non-current	$	4,251			$	5,614			$	12,384		$	—
	__________
	(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 June 30, 2013, $75 million of these interest rate swaps were designated to borrowings on our Revolving Credit Facility and $75 million were designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps are priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that were designated to Black Hills Wyoming were 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 June 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		$	(337	)		Interest expense		$	(926	)				$	—
	Commodity derivatives		(2,737		)		Revenue		(1,251		)				—
	Total		$	(3,074	)				$	(2,177	)				$	—
	Three Months Ended June 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		$	1,067			Interest expense		$	(1,820	)				$	—
	Commodity derivatives		4,985				Revenue		(28		)				—
	Total		$	6,052					$	(1,848	)				$	—
	Six Months Ended June 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		$	(429	)		Interest expense		$	(1,820	)				$	—
	Commodity derivatives		(6,209		)		Revenue		(1,562		)				—
	Total		$	(6,638	)				$	(3,382	)				$	—
	Six Months Ended June 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		$	1,048			Interest expense		$	(3,616	)				$	—
	Commodity derivatives		2,226				Revenue		1,064						—
	Total		$	3,274					$	(2,552	)				$	—
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-Jun-14							31-Dec-13							30-Jun-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)	424,500			9,265,000				412,500			7,082,500				520,500		10,712,500
	Maximum terms in months (b)	1			1				3			1				6		1
	Derivative assets, current	$	—		$	—			$	55		$	—			$	610	$	293
	Derivative assets, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	Derivative liabilities, current	$	—		$	—			$	—		$	—			$	130	$	276
	Derivative liabilities, non-current	$	—		$	—			$	—		$	—			$	—	$	—
	__________
	(a)	Crude oil in Bbls, natural gas in MMBtus.
	(b)	Refers to the term of the derivative instrument. Assets and liabilities are classified as current/non-current based on the term of the hedged transaction 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-Jun-14			31-Dec-13			30-Jun-13
	Derivative assets, current	$	1,737		$	662		$	—
	Derivative assets, non-current	$	—		$	—		$	—
	Derivative liabilities, non-current	$	—		$	—		$	—
	Net unrealized (gain) loss included in Regulatory assets or Regulatory liabilities	$	3,561		$	7,567		$	8,450
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-Jun-14					31-Dec-13					30-Jun-13
		Notional			Maximum		Notional			Maximum		Notional			Maximum
		(MMBtus)			Term		(MMBtus)			Term		(MMBtus)			Term
					(months)					(months)					(months)
	Natural gas futures purchased	16,240,000			78		17,930,000			84		13,330,000			77
	Natural gas options purchased	3,980,000			9		3,890,000			8		2,850,000			5
	Natural gas basis swaps purchased	13,415,000			66		14,785,000			60		10,650,000			66

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 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 June 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	—			—			—		—			—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			600			—		(600		)	—
	Commodity derivatives — Utilities	—			4,342			—		(2,605		)	1,737
	Total	$	—		$	4,942		$	—	$	(3,205	)	$	1,737
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	—		$	—	$	—		$	—
	Basis Swaps -- Oil	—			4,020			—		(4,020		)	—
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			2,030			—		(2,030		)	—
	Commodity derivatives — Utilities	—			5,989			—		(5,989		)	—
	Interest rate swaps	—			7,731			—		—			7,731
	Total	$	—		$	19,770		$	—	$	(12,039	)	$	7,731
		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 June 30, 2013
		Level 1			Level 2			Level 3		Cash Collateral and Counterparty			Total
										Netting
		(in thousands)
	Assets:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	45		$	—	$	(6	)	$	39
	Basis Swaps -- Oil	—			1,109			—		(538		)	571
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			1,882			—		(1,589		)	293
	Commodity derivatives — Utilities	—			1,378			—		(1,378		)	—
	Total	$	—		$	4,414		$	—	$	(3,511	)	$	903
	Liabilities:
	Commodity derivatives — Oil and Gas
	Options -- Oil	$	—		$	181		$	—	$	(98	)	$	83
	Basis Swaps -- Oil	—			350			—		(303		)	47
	Options -- Gas	—			—			—		—			—
	Basis Swaps -- Gas	—			445			—		(169		)	276
	Commodity derivatives — Utilities	—			8,581			—		(8,581		)	—
	Interest rate swaps	—			87,208			—		(5,960		)	81,248
Total	$	—		$	96,765		$	—	$	(15,111	)	$	81,654
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 June 30, 2014
		Balance Sheet Location		Fair Value			Fair Value
				of Asset			of Liability
				Derivatives			Derivatives
	Derivatives designated as hedges:
	Commodity derivatives	Derivative assets — current		$	262		$	—
	Commodity derivatives	Derivative assets — non-current		338			—
	Commodity derivatives	Derivative liabilities — current		—			3,702
	Commodity derivatives	Derivative liabilities — non-current		—			2,348
	Interest rate swaps	Derivative liabilities — current		—			3,480
	Interest rate swaps	Derivative liabilities — non-current		—			4,251
	Total derivatives designated as hedges			$	600		$	13,781
	Derivatives not designated as hedges:
	Commodity derivatives	Derivative assets — current		$	1,737		$	—
	Commodity derivatives	Derivative assets — non-current		—			—
	Commodity derivatives	Derivative liabilities — current		—			—
	Commodity derivatives	Derivative liabilities — non-current		—			3,384
	Total derivatives not designated as hedges			$	1,737		$	3,384
	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 June 30, 2013
		Balance Sheet Location		Fair Value			Fair Value
				of Asset			of Liability
				Derivatives			Derivatives
	Derivatives designated as hedges:
	Commodity derivatives	Derivative assets — current		$	1,225		$	—
	Commodity derivatives	Derivative assets — non-current		1,651			—
	Commodity derivatives	Derivative liabilities — current		—			889
	Commodity derivatives	Derivative liabilities — non-current		—			41
	Interest rate swaps	Derivative liabilities — current		—			6,965
	Interest rate swaps	Derivative liabilities — non-current		—			12,384
	Total derivatives designated as hedges			$	2,876		$	20,279
	Derivatives not designated as hedges:
	Commodity derivatives	Derivative assets — current		$	160		$	—
	Commodity derivatives	Derivative assets — non-current		—			—
	Commodity derivatives	Derivative liabilities — current		—			1,884
	Commodity derivatives	Derivative liabilities — non-current		—			5,365
	Interest rate swaps	Derivative liabilities — current		—			67,859
	Interest rate swaps	Derivative liabilities — non-current		—			—
	Total derivatives not designated as hedges			$	160		$	75,108

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 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-Jun-14				31-Dec-13				30-Jun-13
		Carrying		Fair Value		Carrying		Fair Value		Carrying		Fair Value
		Amount				Amount				Amount
	Cash and cash equivalents (a)	$	14,697	$	14,697	$	7,841	$	7,841	$	30,633	$	30,633
	Restricted cash and equivalents (a)	$	2	$	2	$	2	$	2	$	7,279	$	7,279
	Notes payable (a)	$	132,700	$	132,700	$	82,500	$	82,500	$	100,000	$	100,000
	Long-term debt, including current maturities (b)	$	1,396,950	$	1,578,756	$	1,396,948	$	1,491,422	$	1,214,066	$	1,323,543
	__________
	(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)	6 Months Ended
	Jun. 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						Six Months Ended
			30-Jun-14			30-Jun-13			30-Jun-14			30-Jun-13
	Gains (losses) on cash flow hedges:
	Interest rate swaps	Interest expense	$	926		$	1,820		$	1,820		$	3,616
	Commodity contracts	Revenue	1,251			28			1,562			(1,064		)
			2,177			1,848			3,382			2,552
	Income tax	Income tax benefit (expense)	(774		)	(647		)	(1,199		)	(883		)
	Reclassification adjustments related to cash flow hedges, net of tax		$	1,403		$	1,201		$	2,183		$	1,669
	Amortization of defined benefit plans:
	Prior service cost	Utilities - Operations and maintenance	$	(25	)	$	(31	)	$	(51	)	$	(62	)
		Non-regulated energy operations and maintenance	(84		)	(32		)	(71		)	(64		)
	Actuarial gain (loss)	Utilities - Operations and maintenance	158			421			315			842
		Non-regulated energy operations and maintenance	101			274			186			548
			150			632			379			1,264
	Income tax	Income tax benefit (expense)	(52		)	(268		)	(133		)	(443		)
	Reclassification adjustments related to defined benefit plans, net of tax		$	98		$	364		$	246		$	821
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	)
	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	)

Supplemental_Disclosure_of_Cas1

Supplemental Disclosure of Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Disclosure of Cash Flow Information [Table Text Block]	'
	Six months ended	30-Jun-14			30-Jun-13
		(in thousands)
	Non-cash investing and financing activities from continuing operations—
	Property, plant and equipment acquired with accrued liabilities	$	40,611		$	45,000
	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)	$	(35,009	)	$	(44,191	)
	Income taxes, net	$	(396	)	$	(5,406	)

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	6 Months Ended
	Jun. 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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	1,362		$	1,608		$	2,724		$	3,216
	Interest cost	3,963			3,825			7,926			7,650
	Expected return on plan assets	(4,516		)	(4,654		)	(9,032		)	(9,308		)
	Prior service cost	16			16			32			32
	Net loss (gain)	1,201			3,062			2,403			6,124
	Net periodic benefit cost	$	2,026		$	3,857		$	4,053		$	7,714
	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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	425		$	419		$	850		$	838
	Interest cost	480			417			959			834
	Expected return on plan assets	(21		)	(20		)	(42		)	(40		)
	Prior service cost (benefit)	(107		)	(125		)	(214		)	(250		)
	Net loss (gain)	40			121			80			242
	Net periodic benefit cost	$	817		$	812		$	1,633		$	1,624
	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 June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Service cost	$	374		$	348		$	749		$	696
	Interest cost	362			332			724			664
	Prior service cost	1			1			1			2
	Net loss (gain)	124			198			249			396
	Net periodic benefit cost	$	861		$	879		$	1,723		$	1,758
Schedule of Defined Benefit Plans Contributions [Table Text Block]	'
	Contributions and anticipated contributions are as follows (in thousands):
		Contributions Made			Contributions Made			Additional
		Three Months Ended June 30, 2014			Six Months Ended June 30, 2014			Contributions Anticipated for 2014			Contributions Anticipated for 2015
	Defined Benefit Pension Plans	$	—		$	—		$	—		$	2,806
	Non-pension Defined Benefit Postretirement Healthcare Plans	$	956		$	1,912		$	1,912		$	3,822
	Supplemental Non-qualified Defined Benefit and Defined Contribution Plans	$	373		$	746		$	746		$	1,494

Guarantees_Tables

Guarantees (Tables)	6 Months Ended
	Jun. 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-Jun-14		Expiration
	Indemnification for subsidiary reclamation/surety bonds (1)	$	65,744	Ongoing
	_______________________
	-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.
	During the second quarter, 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.

Information_Relating_to_Segmen

Information Relating to Segment Statement of Income (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	$283,237,000	$279,826,000		$743,406,000	$660,497,000
Net Income (Loss)	19,820,000	30,518,000		67,938,000	73,715,000
Mark-to-market gain (loss) on certain interest rate swaps, net of tax	'	12,000,000		'	17,000,000
Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	-32,925,000	-30,299,000		-66,891,000	-61,357,000
Net Income (Loss)	0	-3,000		0	0
Corporate activities[Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	0	0		0	0
Net Income (Loss)	-1,151,000	11,679,000	[1]	-821,000	17,378,000	[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	158,740,000	154,338,000		336,835,000	312,821,000
Net Income (Loss)	11,427,000	10,610,000		26,002,000	22,966,000
Electric Utilities [Member] | Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	3,144,000	3,694,000		7,151,000	7,841,000
Gas Utilities [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	102,499,000	105,836,000		361,836,000	305,648,000
Net Income (Loss)	1,994,000	3,192,000		26,692,000	21,675,000
Gas Utilities [Member] | Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	0	0		0	0
Power Generation [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	1,267,000	1,031,000		2,536,000	2,053,000
Net Income (Loss)	7,194,000	5,031,000		15,267,000	10,675,000
Power Generation [Member] | Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	20,713,000	19,094,000		41,792,000	38,432,000
Coal Mining [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	5,583,000	6,807,000		12,201,000	12,817,000
Net Income (Loss)	2,016,000	1,973,000		4,480,000	3,038,000
Coal Mining [Member] | Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	9,068,000	7,511,000		17,948,000	15,084,000
Oil and Gas [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	15,148,000	11,814,000		29,998,000	27,158,000
Net Income (Loss)	-1,660,000	-1,964,000		-3,682,000	-2,017,000
Oil and Gas [Member] | Intersegment Elimination [Member]	'	'		'	'
Segment Reporting Information [Line Items]	'	'		'	'
Revenue, Net	$0	$0		$0	$0
[1]	Corporate activities include a $12 million and a $17 million after-tax non-cash mark-to-market gain for the three and six months ended June 30, 2013, respectively on certain interest rate swaps.

Segment_and_Corporate_Assets_D

Segment and Corporate Assets (Details) (USD $)	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	$3,970,498		$3,875,178		$3,746,514
Corporate activities[Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	100,426		80,731		146,302
Electric Utilities [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	2,603,900	[1]	2,525,947	[1]	2,417,952	[1]
Gas Utilities [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	799,365		805,617		734,337
Power Generation [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	85,269	[1]	95,692	[1]	108,515	[1]
Coal Mining [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	73,701		78,825		82,553
Oil and Gas [Member]	'		'		'
Segment Reporting, Asset Reconciling Item [Line Items]	'		'		'
Assets	$307,837		$288,366		$256,855
[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 $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	($1,662)	($1,237)	($1,723)
Accounts receivable, net	135,145	177,573	132,726
Corporate[Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	2,012	604	1,935
Electric Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-622	-666	-630
Accounts receivable, net	69,427	75,594	68,910
Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-1,027	-558	-1,074
Accounts receivable, net	51,342	89,799	50,867
Power Generation [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	1,388	1,722	157
Coal Mining [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	0	0	0
Accounts receivable, net	1,866	1,711	2,503
Oil and Gas [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Allowance for Doubtful Accounts Receivable	-13	-13	-19
Accounts receivable, net	9,110	8,143	8,354
Billed Revenues [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	105,826	113,792	96,967
Billed Revenues [Member] | Corporate[Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	2,012	604	1,935
Billed Revenues [Member] | Electric Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	48,333	52,437	45,250
Billed Revenues [Member] | Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	43,104	49,162	38,749
Billed Revenues [Member] | Power Generation [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	1,388	1,722	157
Billed Revenues [Member] | Coal Mining [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	1,866	1,711	2,503
Billed Revenues [Member] | Oil and Gas [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	9,123	8,156	8,373
Unbilled Revenues [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	30,981	65,018	37,482
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	21,716	23,823	24,290
Unbilled Revenues [Member] | Gas Utilities [Member]	'	'	'
Accounts Receivable [Line Items]	'	'	'
Accounts Receivable, Trade	9,265	41,195	13,192
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 $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets	$202,961		$162,648		$206,904
Regulatory Liabilities	120,290		120,156		149,563
Deferred energy and gas costs	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P1Y		'		'
Regulatory Liabilities	6,490	[1]	11,708	[1]	22,340	[1]
Employee benefit plans	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P13Y		'		'
Regulatory Liabilities	34,356	[2]	34,431	[2]	60,214	[2]
Cost of removal	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P44Y		'		'
Regulatory Liabilities	70,841	[1]	64,970	[1]	59,461	[1]
Other regulatory liabilities	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Liabilities Amortization Period (in years)	'P25Y		'		'
Regulatory Liabilities	8,603	[2]	9,047	[2]	7,548	[2]
Deferred energy and fuel cost adjustments - current	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets	29,605	[1],[3]	16,775	[1],[3]	15,951	[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	39,040	[1],[3]	12,366	[1],[3]	13,090	[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	12,468	[4]	12,315	[4]	12,456	[4]
Employee benefit plans	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P13Y		'		'
Regulatory Assets	65,874	[2]	67,059	[2]	115,379	[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]	1,798	[1]
Asset retirement obligations	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P44Y		'		'
Regulatory Assets	3,278	[1]	3,266	[1]	3,257	[1]
Bond issue cost	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P24Y		'		'
Regulatory Assets	3,347	[1]	3,419	[1]	3,489	[1]
Renewable energy standard adjustment	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P5Y		'		'
Regulatory Assets	14,501	[1]	14,186	[1]	14,694	[1]
Flow through accounting	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P35Y		'		'
Regulatory Assets	22,754	[2]	20,916	[2]	17,995	[2]
Other regulatory assets	'		'		'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'		'		'
Regulatory Assets Amortization Period (in years)	'P15Y		'		'
Regulatory Assets	$10,780	[1]	$10,546	[1]	$8,795	[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 June 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 $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Inventory, Net [Abstract]	'	'	'
Materials and supplies	$51,925	$50,196	$51,334
Fuel - Electric Utilities	7,679	6,213	6,817
Natural gas in storage held for distribution	21,560	32,069	15,617
Total materials, supplies and fuel	$81,164	$88,478	$73,768

Basic_to_Dilutive_EPS_Details

Basic to Dilutive EPS (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]	'	'	'	'
Net income (loss) available for common stock	$19,820	$30,518	$67,938	$73,715
Weighted average shares - basic	44,399	44,172	44,365	44,113
Dilutive Effect on Basic Earnings Per Share [Abstract]	'	'	'	'
Equity compensation, shares	189	240	206	250
Weighted average shares - diluted	44,588	44,412	44,571	44,363

Earnings_Per_Share_Antidilutiv

Earnings Per Share Anti-dilutive shares (Details)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Shares	81	28	63	34
Equity compensation [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Shares	81	28	63	34

Notes_Payable_Details

Notes Payable (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Balance Outstanding	$132,700,000	$82,500,000	$100,000,000
Revolving Credit Facility [Member]	'	'	'
Line of Credit Facility [Line Items]	'	'	'
Revolving Credit Facility - Balance Outstanding	132,700,000	82,500,000	100,000,000
Revolving Credit Facility - Letters of Credit Outstanding	20,272,000	22,100,000	43,157,000
Revolving Credit Facility - Current Borrowing Capacity	500,000,000	'	'
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 $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'	'
Current maturities of long-term debt	$275,000	$0	$255,507
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 $)	6 Months Ended				12 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Derivative [Line Items]	'		'		'
Credit Exposure, Non-Investment Grade Company	$500,000		'		'
Derivative assets, current	1,737,000		903,000		717,000
Derivative liabilities, current	3,480,000		69,270,000		3,474,000
Derivative liabilities, non-current	4,251,000		12,384,000		5,614,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative liabilities, current	3,480,000		6,965,000		3,474,000
Derivative liabilities, non-current	4,251,000		12,384,000		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 6 months		'3 years 6 months		'3 years
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	-3,500,000		'		'
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative liabilities, current	'		61,899,000		'
Derivative liabilities, non-current	'		0		'
Derivative, Notional Amount	'		250,000,000	[3]	'
Weighted Average Fixed Interest Rate	'		5.67%		'
Derivative, Remaining Maturity	'		'0 years 6 months		'
Oil and Gas [Member]	'		'		'
Derivative [Line Items]	'		'		'
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	-3,400,000		'		'
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	1,737,000		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	3,561,000		8,450,000		7,567,000
Natural Gas, Distribution [Member] | Utilities Group [Member] | Future [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	16,240,000		13,330,000		17,930,000
Derivative, Remaining Maturity	'78 months		'77 months		'84 months
Natural Gas, Distribution [Member] | Utilities Group [Member] | Commodity Option [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	3,980,000		2,850,000		3,890,000
Derivative, Remaining Maturity	'9 months		'5 months		'8 months
Natural Gas, Distribution [Member] | Utilities Group [Member] | Basis Swap [Member] | Purchase Contract [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	13,415,000		10,650,000		14,785,000
Derivative, Remaining Maturity	'66 months		'66 months		'60 months
Crude Oil [Member] | Oil and Gas [Member] | Swaps and Options [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	424,500	[4]	520,500	[4]	412,500	[4]
Maximum terms in months - Hedged in Cash Flow Hedge	'1 month	[5]	'6 months	[5]	'3 months	[5]
Derivative assets, current	0		610,000		55,000
Derivative assets, non-current	0		0		0
Derivative liabilities, current	0		130,000		0
Derivative liabilities, non-current	0		0		0
Natural Gas [Member] | Oil and Gas [Member] | Swap [Member]	'		'		'
Derivative [Line Items]	'		'		'
Derivative, Nonmonetary Notional Amount	9,265,000	[4]	10,712,500	[4]	7,082,500	[4]
Maximum terms in months - Hedged in Cash Flow Hedge	'1 month	[5]	'1 month	[5]	'1 month	[5]
Derivative assets, current	0		293,000		0
Derivative assets, non-current	0		0		0
Derivative liabilities, current	0		276,000		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 June 30, 2013, $75 million of these interest rate swaps were designated to borrowings on our Revolving Credit Facility and $75 million were designated to borrowings on our project financing debt at Black Hills Wyoming. These swaps are priced using three-month LIBOR, matching the floating portion of the related debt. The portion of the swaps that were designated to Black Hills Wyoming were 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]	Crude oil in Bbls, natural gas in MMBtus.
[5]	Refers to the term of the derivative instrument. Assets and liabilities are classified as current/non-current based on the term of the hedged transaction 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		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	($3,074)	$6,052	($6,638)	$3,274
Amount of Reclassified Gain/(Loss) from AOCI into Income (Effective Portion)	-2,177	-1,848	-3,382	-2,552
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)	-337	1,067	-429	1,048
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)	-926	-1,820	-1,820	-3,616
Commodity Contract [Member]	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Amount of Gain/(Loss) Recognized in AOCI Derivative (Effective Portion)	-2,737	4,985	-6,209	2,226
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)	-1,251	-28	-1,562	1,064
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 $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 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	4,942	3,975	4,414
Liabilities, Fair Value Disclosure	19,770	19,948	96,765
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	7,731	9,088	87,208
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	45
Derivative Liabilities	0	0	181
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	0	130	1,109
Derivative Liabilities	4,020	1,229	350
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	600	815	1,882
Derivative Liabilities	2,030	531	445
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	4,342	3,030	1,378
Derivative Liabilities	5,989	9,100	8,581
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	-3,205	-3,258	-3,511
Liabilities, Fair Value Disclosure	-12,039	-10,860	-15,111
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	-6
Derivative Liabilities	0	0	-98
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	0	-75	-538
Derivative Liabilities	-4,020	-1,229	-303
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	-600	-815	-1,589
Derivative Liabilities	-2,030	-531	-169
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	-2,605	-2,368	-1,378
Derivative Liabilities	-5,989	-9,100	-8,581
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	1,737	717	903
Liabilities, Fair Value Disclosure	7,731	9,088	81,654
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	7,731	9,088	81,248
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	39
Derivative Liabilities	0	0	83
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	571
Derivative Liabilities	0	0	47
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	293
Derivative Liabilities	0	0	276
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	1,737	662	0
Derivative Liabilities	$0	$0	$0

Fair_Value_Measurements_Balanc

Fair Value Measurements - Balance Sheet Location (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Designated as Hedging Instrument [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Net	$600	$946	$2,876
Derivative Liability, Fair Value, Net	13,781	10,848	20,279
Not Designated as Hedging Instrument [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Net	1,737	662	160
Derivative Liability, Fair Value, Net	3,384	6,732	75,108
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Derivative Assets, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	262	248	1,225
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	338	698	1,651
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	3,702	1,541	889
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	2,348	219	41
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivative Assets, Current [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative Asset, Fair Value, Gross Asset	1,737	662	160
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	0	0	1,884
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	3,384	6,732	5,365
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	3,480	3,474	6,965
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	4,251	5,614	12,384
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	'	'	67,859
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 $)	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and cash equivalents	$14,697		$7,841		$30,633
Restricted cash and equivalents	2		2		7,279
Notes payable	132,700		82,500		100,000
Carrying Value [Member]	'		'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and cash equivalents	14,697		7,841		30,633
Restricted cash and equivalents	2		2		7,279
Notes payable	132,700		82,500		100,000
Long-term debt, including current maturities	1,396,950		1,396,948		1,214,066
Fair Value [Member]	'		'		'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'
Cash and Cash Equivalents, Fair Value	14,697	[1]	7,841	[1]	30,633	[1]
Restricted Cash and equivalents, Fair Value	2	[1]	2	[1]	7,279	[1]
Notes payable, Fair Value	132,700	[1]	82,500	[1]	100,000	[1]
Long-term debt, including current maturities, Fair Value	$1,578,756	[2]	$1,491,422	[2]	$1,323,543	[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		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Interest expense	$17,886	$23,369	$35,746	$47,041
Revenue	283,237	279,826	743,406	660,497
Utilities - Operating and Maintenance	66,074	64,977	137,301	130,667
Non-regulated energy operations and maintenance	21,350	20,890	43,682	42,219
Income (loss) before earnings (loss) of unconsolidated subsidiaries and income taxes	30,471	46,134	103,955	110,994
Income tax benefit (expense)	-10,651	-15,616	-36,017	-37,193
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	2,177	1,848	3,382	2,552
Income tax benefit (expense)	-774	-647	-1,199	-883
Net income (loss) available for common stock	1,403	1,201	2,183	1,669
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	926	1,820	1,820	3,616
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	1,251	28	1,562	-1,064
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	-25	-31	-51	-62
Non-regulated energy operations and maintenance	-84	-32	-71	-64
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	421	315	842
Non-regulated energy operations and maintenance	101	274	186	548
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	150	632	379	1,264
Income tax benefit (expense)	-52	-268	-133	-443
Net income (loss) available for common stock	$98	$364	$246	$821

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax	($19,441)	($18,589)	($30,781)	($36,224)	($19,441)	($30,781)	($17,422)	($35,488)
Other Comprehensive Income (Loss), Net of Tax	-852	-1,167	5,443	-736	-2,019	4,707	'	'
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-9,167	-8,611	-11,827	-16,906	-9,167	-11,827	-7,133	-15,713
Other Comprehensive Income (Loss), Net of Tax	-556	-1,478	5,079	-1,193	'	'	'	'
Accumulated Defined Benefit Plans Adjustment [Member]	'	'	'	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	-10,274	-9,978	-18,954	-19,318	-10,274	-18,954	-10,289	-19,775
Other Comprehensive Income (Loss), Net of Tax	($296)	$311	$364	$457	'	'	'	'

Supplemental_Disclosure_of_Cas2

Supplemental Disclosure of Cash Flow Information (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Non-cash Investing and Financing Activities from Continuing Operations [Abstract]	'	'
Property, plant and equipment acquired wtih accrued liabilities	$40,611	$45,000
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)	-35,009	-44,191
Income taxes, net	($396)	($5,406)

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Defined Benefit Pension Plans	'	'	'	'
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'
Service cost	$1,362	$1,608	$2,724	$3,216
Interest cost	3,963	3,825	7,926	7,650
Expected return on plan assets	-4,516	-4,654	-9,032	-9,308
Prior service cost (benefit)	16	16	32	32
Net loss (gain)	1,201	3,062	2,403	6,124
Net periodic benefit cost	2,026	3,857	4,053	7,714
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	0	'	0	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	0	'
Estimated Future Employer Contributions in Next Fiscal Year	'	'	2,806	'
Non-pension Defined Benefit Postretirement Healthcare Plans	'	'	'	'
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]	'	'	'	'
Service cost	425	419	850	838
Interest cost	480	417	959	834
Expected return on plan assets	-21	-20	-42	-40
Prior service cost (benefit)	-107	-125	-214	-250
Net loss (gain)	40	121	80	242
Net periodic benefit cost	817	812	1,633	1,624
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	956	'	1,912	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	1,912	'
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	749	696
Interest cost	362	332	724	664
Prior service cost (benefit)	1	1	1	2
Net loss (gain)	124	198	249	396
Net periodic benefit cost	861	879	1,723	1,758
Pension and Other Postretirement Benefit Contributions [Abstract]	'	'	'	'
Contributions by Employer	373	'	746	'
Estimated Future Employer Contributions in Current Fiscal Year	'	'	746	'
Estimated Future Employer Contributions in Next Fiscal Year	'	'	$1,494	'

Commitments_and_Contingencies_

Commitments and Contingencies - Bond Purchase Agreement (Details) (First Mortgage Bonds Due 2044 [Member], Electric Utilities [Member], USD $)	Jun. 30, 2014
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'
Debt Instrument Aggregate Principal Amount Entered Into Private Placement	$160
Black Hills Power [Member]	'
Debt Instrument [Line Items]	'
Debt Instrument Aggregate Principal Amount Entered Into Private Placement	85
Debt Instrument, Interest Rate, Stated Percentage	4.43%
Cheyenne Light [Member]	'
Debt Instrument [Line Items]	'
Debt Instrument Aggregate Principal Amount Entered Into Private Placement	$75
Debt Instrument, Interest Rate, Stated Percentage	4.53%

Commitments_and_Contingencies_1

Commitments and Contingencies - Purchase Sales Agreement (Details) (Power Generation [Member], CTII Natural Gas Fired Generating Unit [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	6-May-13
Power Generation [Member] | CTII Natural Gas Fired Generating Unit [Member]	'
Future Consideration from Sale of Assets	$22

Commitments_and_Contingencies_2

Commitments and Contingencies - Reimbursement Agreement (Details) (Surety Bond [Member], Electric Utilities [Member], USD $)	Jun. 30, 2014
In Thousands, unless otherwise specified
Industrial Development Revenue Bonds Due 2027 [Member]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	$10,000
Industrial Development Revenue Bonds Due 2021 [Member]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	$7,000

Commitments_and_Contingencies_3

Commitments and Contingencies - Other Commitments (Details) (Cheyenne Prairie [Member], USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Long-term Purchase Commitment [Line Items]	'
Long-term Purchase Commitment, Amount	$222
Equipment [Member]	'
Long-term Purchase Commitment [Line Items]	'
Long Term Purchase Commitment, Percentage Committed	100.00%
Construction Contracts [Member]	'
Long-term Purchase Commitment [Line Items]	'
Long Term Purchase Commitment, Percentage Committed	98.00%

Commitments_and_Contingencies_4

Commitments and Contingencies - Oil Creek Fire (Details) (Oil Creek Fire [Member], Loss from Catastrophes [Member], USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 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_5

Commitments and Contingencies - Dividend Restrictions (Details) (Utilities Group [Member], USD $)	Jun. 30, 2014
In Millions, unless otherwise specified
Utilities Group [Member]	'
Related Party Transaction [Line Items]	'
Restricted Net Assets for Subsidiaries	$141

Guarantees_Details

Guarantees (Details) (USD $)	Jun. 30, 2014
In Thousands, unless otherwise specified
Coal Mining [Member] | Surety Bond [Member]	'
Statement [Line Items]	'
Guarantor Obligations, Maximum Exposure, Undiscounted	$65,744	[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.