Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Operating activities
Net income	$ 64,208	$ 29,720
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Unrealized (gain) loss on derivatives	(7,950)	6,626
Depletion, depreciation and amortization	90,970	74,593
Accretion of asset retirement obligations	371	248
Full-cost ceiling impairment	0	21,229
Stock-based compensation expense	4,665	2,763
Deferred income tax provision	34,017	1,661
Gain (Loss) on Sale of Assets and Asset Impairment Charges	0	192
Changes in operating assets and liabilities
Accounts receivable	(12,605)	(886)
Lease and Well Equipment Inventory	(193)	198
Prepaid expenses	(74)	(2,148)
Other assets	(810)	(728)
Accounts payable, accrued liabilities and other current liabilities	(820)	(10,702)
Royalties payable	6,175	3,812
Advances from joint interest owners	0	(1,505)
Income taxes payable	2,565	980
Other long-term liabilities	(160)	1,139
Net cash provided by operating activities	180,359	127,192
Investing activities
Oil and natural gas properties capital expenditures	(407,023)	(257,216)
Expenditures for other property and equipment	(2,906)	(3,058)
Purchases of certificates of deposit	0	(61)
Maturities of certificates of deposit	0	251
Net cash used in investing activities	(409,929)	(260,084)
Financing activities
Repayments of Lines of Credit	(180,000)	(130,000)
Borrowings under Credit Agreement	230,000	125,000
Proceeds from Issuance of Common Stock	181,875	149,069
Payments of Stock Issuance Costs	(590)	(6,933)
Proceeds from stock options exercised	6	0
Payments Related to Tax Withholding for Share-based Compensation	(285)	(9)
Net cash provided by financing activities	231,006	137,127
Increase (decrease) in cash	1,436	4,235
Cash at beginning of period	6,287	2,095
Cash at end of period	$ 7,723	$ 6,330