Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities
Net income	$ 34,589	$ 9,615
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Unrealized loss (gain) on derivatives	8,342	(2,701)
Depletion, depreciation and amortization	55,827	48,466
Accretion of asset retirement obligations	241	161
Full-cost ceiling impairment	0	21,229
Stock-based compensation expense	3,629	1,524
Deferred income tax provision	17,356	0
Net loss on asset sales and inventory impairment	0	192
Changes in operating assets and liabilities
Accounts receivable	(13,338)	1,763
Lease and well equipment inventory	(36)	280
Prepaid expenses	(656)	(215)
Other assets	(468)	(117)
Accounts payable, accrued liabilities and other current liabilities	(517)	4,615
Royalties payable	5,890	(206)
Advances from joint interest owners	0	(1,515)
Income taxes payable	2,814	78
Other long-term liabilities	(198)	743
Net cash provided by operating activities	113,475	83,912
Investing activities
Oil and natural gas properties capital expenditures	(234,335)	(173,989)
Expenditures for other property and equipment	(1,884)	(2,081)
Purchases of certificates of deposit	0	(61)
Maturities of certificates of deposit	0	230
Net cash used in investing activities	(236,219)	(175,901)
Financing activities
Repayments of Lines of Credit	(180,000)	0
Borrowings under Credit Agreement	130,000	95,000
Proceeds from Issuance of Common Stock	181,875	0
Payments of Stock Issuance Costs	(504)	0
Proceeds from stock options exercised	6	0
Payments Related to Tax Withholding for Share-based Compensation	(285)	(1)
Net cash provided by financing activities	131,092	94,999
Increase (decrease) in cash	8,348	3,010
Cash at beginning of period	6,287	2,095
Cash at end of period	$ 14,635	$ 5,105