Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net Income	$ 3,570	[1]	$ 20,181
Other Comprehensive Income:
Unrealized gains related to price risk management transactions, before taxes	212		19
Provision for income taxes	77		7
Unrealized gains (losses) related to price risk management transactions, net of taxes	135		12
Less: reclassification of (gains) losses on price risk management transactions to net income, before taxes	198		(167)
(Provision) benefit for income taxes	72		(60)
Reclassification of (gains) losses on price risk management transactions to net income, net of taxes	126		(107)
Other comprehensive income (loss), before income taxes	410		(148)
Provision (benefit) for income taxes	149		(54)
Other comprehensive income (loss), net of taxes	261	[1]	(94)
Comprehensive Income	$ 3,831		$ 20,087

[1] (2) Unaudited