Consolidated statements of comprehensive income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Comprehensive income
Net income	$ 55,687	$ 64,403	$ 42,048
Other comprehensive (loss) income
Reclassification adjustment for hedge (gains) losses included in gain (loss) from oil hedging activities in the consolidated statements of operations	(37,134)	(46,746)	27,452
Income tax expense (benefit) related to other comprehensive income (loss)	13,911	18,123	(10,580)
Other comprehensive (loss) income, net of tax	(23,223)	(28,623)	16,872
Comprehensive income	$ 32,464	$ 35,780	$ 58,920