Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net Income	$ 26,182	$ 9,423
(Income) loss from discontinued operations, net of income taxes	(23,658)	1,253
Adjustments to reconcile net income from continuing operations to net cash provided by operating activities-
Depreciation, depletion and amortization	45,590	31,561
Unrealized (gain) loss on derivative instruments, net	20,269	7,330
Accretion related to asset retirement obligations	107	102
Stock-based compensation, net of amounts capitalized	6,483	4,016
Allowance for doubtful accounts	(575)	40
Deferred income taxes	1,449	5,285
Amortization of debt discount and deferred financing costs, net of amounts capitalized	1,309	1,033
Other, net	27	1,174
Changes in operating assets and liabilities-
Accounts receivable	2,216	(20,746)
Accounts payable	29,337	27,892
Accrued liabilities	(16,398)	16,692
Other, net	(1,156)	(1,377)
Net cash provided by operating activities - continuing operations	91,182	83,678
Net cash used in operating activities - discontinued operations	(61)	(436)
Net cash provided by operating activities	91,121	83,242
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures - oil and gas properties	(230,244)	(191,059)
Capital expenditures - other property and equipment	(999)	(2,721)
Increase (decrease) in capital expenditure payables and accruals	16,984	6,264
Proceeds from sales of U.S. oil and gas properties, net	9,063	693
Advances to operators	1,942	94
Advances for joint operations	10,050	(28,535)
Other, net	1,243	(1,416)
Net cash used in investing activities - continuing operations	(191,961)	(216,680)
Net cash used in investing activities - discontinued operations	116,179	(10,241)
Net cash used in investing activities	(75,782)	(226,921)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from borrowings and issuances	45,000	238,685
Debt repayments	(45,000)	(109,000)
Payments of costs associated with revolving credit facility and debt issuance	(50)	(222)
Proceeds from stock options exercised	743	0
Net cash provided by financing activities - continuing operations	693	129,463
Net cash provided by financing activities - discontinued operations	3,000	9,673
Net cash provided by financing activities	3,693	139,136
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	19,032	(4,543)
CASH AND CASH EQUIVALENTS, beginning of period	52,614	28,112
CASH AND CASH EQUIVALENTS, end of period	$ 71,646	$ 23,569