Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]
Net income	$ 92,084	$ 67,672
(Income) loss from discontinued operations, net of income taxes	748	(23,599)
Adjustments to reconcile income from continuing operations to net cash provided by operating activities from continuing operations
Depreciation, depletion and amortization	228,912	151,587
Non-cash (gain) loss on derivatives, net	(36,652)	25,806
Stock-based compensation	28,209	19,338
Deferred Income Tax Expense (Benefit)	48,908	25,853
Non-cash interest expense, net	2,021	3,217
Other, net	(1,705)	1,789
Changes in operating assets and liabilities-
Accounts receivable	(1,767)	1,910
Accounts payable	33,024	38,843
Accrued liabilities	(771)	2,049
Other, net	(4,324)	(4,212)
Net cash provided by operating activities from continuing operations	388,687	310,253
Net cash used in operating activities from discontinued operations	(1,162)	(400)
Net cash provided by operating activities	387,525	309,853
Cash Flows From Investing Activities
Capital expenditures - oil and gas properties	(665,517)	(548,049)
Capital expenditures - other property and equipment	(569)	(687)
Proceeds from sales of oil and gas properties, net	10,487	20,753
Other, net	1,418	24,582
Net cash used in investing activities from continuing operations	(654,181)	(503,401)
Net cash provided by (used in) investing activities from discontinued operations	(6,773)	126,223
Net cash used in investing activities	(660,954)	(377,178)
Cash Flows From Financing Activities
Proceeds from borrowings and issuances	646,000	437,000
Debt repayments	(527,000)	(419,325)
Payments of debt issuance costs	(594)	(1,075)
Excess Tax Benefit from Share-based Compensation, Financing Activities	4,602	0
Proceeds from stock options exercised	143	839
Net cash provided by financing activities from continuing operations	123,151	17,439
Net cash provided by financing activities from discontinued operations	0	3,000
Net cash provided by financing activities	123,151	20,439
Net Decrease in Cash and Cash Equivalents	(150,278)	(46,886)
Cash and Cash Equivalents, Beginning of Period	157,439	52,614
Cash and Cash Equivalents, End of Period	$ 7,161	$ 5,728