Related Party Transactions Related Party Transactions (Tables)

3 Months Ended

Mar. 31, 2013

Related Party Transaction [Line Items]

Schedule of Related Party Accounts Receivable and Payable [Table Text Block]

The balances were as follows (in thousands) as of:

	March 31, 2013		December 31, 2012
Receivables - affiliates	$	4,896	$	5,027
Accounts payable - affiliates	$	18,030	$	21,896

Schedule of Related Party Notes [Table Text Block]

We had the following balances with the Utility Money Pool (in thousands) as of:

	March 31, 2013		December 31, 2012
Money pool notes receivable, net	$	35,063	$	31,645

Schedule of Related Party Interest Income Expense [Table Text Block]

Net interest income (expense) relating to balances for the Utility Money Pool was as follows (in thousands):

	Three Months Ended March 31,
	2013			2012
Net interest income (expense)	$	(440	)	$	283

Schedule of Revenues and Purchases from Related Parties [Table Text Block]

Sales and purchases with related parties were as follows (in thousands):

	Three Months Ended March 31,
	2013		2012
Revenues:
Energy sold to Cheyenne Light	$	140	$	526
Rent from electric properties	$	988	$	1,259
Purchases:
Purchase of coal from WRDC	$	4,524	$	5,995
Purchase of excess energy from Cheyenne Light	$	946	$	742
Purchase of renewable wind energy from Cheyenne Light - Happy Jack	$	650	$	671
Purchase of renewable wind energy from Cheyenne Light - Silver Sage	$	1,085	$	1,077
Purchase of natural gas - other	$	—	$	7
Corporate support services from Parent, Black Hills Service Company and Black Hills Utilities Holdings Inc.	$	7,276	$	4,805