Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 3,028	$ 41,028	$ 6,598	[1]	$ 61,209
Other Comprehensive Income:
Unrealized gains (losses) related to price risk management transactions, before taxes	958	(352)	1,171		(333)
Provision (benefits) for income taxes	349	(128)	426		(121)
Unrealized gains (losses) related to price risk management transactions, net of taxes	609	(224)	745		(212)
Less: reclassification of (gains) losses on price risk management transactions to net income, before taxes	(1,369)	1,050	(1,171)		883
(Provision) benefit for income taxes	(498)	384	(426)		324
Reclassification of (gains) losses on price risk management transactions to net income, net of taxes	(871)	666	(745)		559
Other comprehensive income (loss), before income taxes	(411)	698	0		550
Provision (benefit) for income taxes	(150)	256	0		202
Other comprehensive income (loss), net of taxes	(261)	442	0	[1]	348
Comprehensive Income	$ 2,767	$ 41,470	$ 6,598		$ 61,557

[1] Unaudited