CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 10,708	$ 9,175	$ 20,512	$ 21,097	$ 54,387	$ 52,537
Reclassification adjustments for loss included in net income or reclassified to regulatory asset or liability						4,864
Net change in fair market value of open derivative contracts for period						(1,037)
Income taxes						(1,458)
Comprehensive income	$ 10,708	$ 9,175	$ 20,512	$ 21,097	$ 54,387	$ 54,906