Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 6,722	$ 3,028	$ 13,931	$ 6,598
Other Comprehensive Income:
Unrealized gains (losses) related to price risk management transactions, before taxes	0	958	0	1,171
Provision (benefits) for income taxes	0	349	0	426
Unrealized gains (losses) related to price risk management transactions, net of taxes	0	609	0	745
Less: reclassification of (gains) losses on price risk management transactions to net income, before taxes	0	(1,369)	0	(1,171)
(Provision) benefit for income taxes	0	(498)	0	(426)
Reclassification of (gains) losses on price risk management transactions to net income, net of taxes	0	(871)	0	(745)
Other comprehensive income (loss), before income taxes	0	(411)	0	0
Provision (benefit) for income taxes	0	(150)	0	0
Other comprehensive income (loss), net of taxes	0	(261)	0	0
Comprehensive Income	$ 6,722	$ 2,767	$ 13,931	$ 6,598