Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 3,122	$ 16,976	$ 9,720	$ 78,185
Other Comprehensive Income:
Unrealized gains (losses) related to price risk management transactions, before taxes	66	(72)	1,237	(405)
Provision (benefits) for income taxes	24	(27)	450	(148)
Unrealized gains (losses) related to price risk management transactions, net of taxes	42	(45)	787	(257)
Less: reclassification of (gains) losses on price risk management transactions to net income, before taxes	(244)	(260)	(1,415)	623
(Provision) benefit for income taxes	(89)	(95)	(515)	229
Reclassification of (gains) losses on price risk management transactions to net income, net of taxes	(155)	(165)	(900)	394
Other comprehensive income (loss), before income taxes	(178)	(332)		218
Accumulated Other Comprehensive Income (Loss), Gross			(178)
Provision (benefit) for income taxes	(65)	(122)		80
Accumulated Other Comprehensive Income (Loss) Tax Effect			(65)
Other comprehensive income (loss), net of taxes	(113)	(210)	(113)	138
Comprehensive Income	$ 3,009	$ 16,766	$ 9,607	$ 78,323