Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 7,209	$ 3,570
Other Comprehensive Income:
Unrealized gains (losses) related to price risk management transactions, before taxes	0	212
Provision (benefits) for income taxes	0	77
Unrealized gains (losses) related to price risk management transactions, net of taxes	0	135
Less: reclassification of (gains) losses on price risk management transactions to net income, before taxes	0	198
(Provision) benefit for income taxes	0	72
Reclassification of (gains) losses on price risk management transactions to net income, net of taxes	0	126
Other comprehensive income (loss), before income taxes	0	410
Provision (benefit) for income taxes	0	149
Other comprehensive income (loss), net of taxes	0	261
Comprehensive Income	$ 7,209	$ 3,831