Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating activities
Net (loss) income	$ (16,363)	$ 15,505
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Unrealized loss on derivatives	3,108	4,825
Depletion, depreciation and amortization	24,030	28,232
Accretion of asset retirement obligations	117	81
Full-cost ceiling impairment	0	21,230
Stock-based compensation expense	(1,795)	(492)
Deferred income tax provision	8,261
Changes in operating assets and liabilities
Accounts receivable	(6,941)	1,752
Lease and well equipment inventory	(31)	121
Prepaid expenses	(424)	(493)
Other assets	(466)	(172)
Accounts payable, accrued liabilities and other current liabilities	(16,540)	(10,788)
Royalties payable	(1,597)	(1,165)
Advances from joint interest owners	0	1,034
Income taxes payable	1,275	46
Other long-term liabilities	(199)	209
Net cash provided by operating activities	31,945	32,229
Investing activities
Oil and natural gas properties capital expenditures	(92,891)	(83,387)
Expenditures for other property and equipment	(1,007)	(1,374)
Purchases of certificates of deposit	0	(61)
Maturities of certificates of deposit	0	150
Net cash used in investing activities	(93,898)	(84,672)
Financing activities
Borrowings under Credit Agreement	70,000	55,000
Proceeds from stock options exercised	6	0
Net cash provided by financing activities	70,006	55,000
Increase (decrease) in cash	8,053	2,557
Cash at beginning of period	6,287	2,095
Cash at end of period	$ 14,340	$ 4,652