CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities
Net loss	$ (132,915)	$ 19,667	$ (77,368)
Adjustments to reconcile net loss to net cash provided by operating activities from continuing operations:
Income from discontinued operations		(36,832)	(64,130)
Gain on sale of discontinued operations		(86,662)
Non-cash portion of loss on extinguishment of debt	22,456
Depreciation, depletion and amortization	162,534	134,700	154,351
Impairments	104,688	45,959	106,415
Derivative contracts:
Net gains	(15,651)	(41,906)	(28,033)
Cash settlements	27,380	32,818	58,147
Deferred income taxes (benefit)	(85,501)	42,528	(83,222)
Loss (gain) on sales of property and equipment, net	(2,474)	61	(1,910)
Dry hole and unproved leasehold expense	60,940	36,275	33,278
Non-cash interest expense	6,807	11,984	10,202
Share-based compensation	7,430	7,811	9,127
Other, net	275	(209)	683
Changes in operating assets and liabilities:
Accounts receivable, net	(1,792)	(19,964)	33,266
Accounts payable and accrued expenses	(6,552)	10,877	(20,066)
Other assets and liabilities	(2,884)	(77,268)	(13,007)
Net cash provided by operating activities from continuing operations	144,741	79,839	117,733
Cash flows from investing activities
Capital expenditures - property and equipment	(445,623)	(405,994)	(205,676)
Proceeds from the sale of PVG units, net (Note 3)		139,120
Proceeds from sales of property and equipment, net	39,368	25,567	15,083
Other, net	100	1,192	11
Net cash used in investing activities for continuing operations	(406,155)	(240,115)	(190,582)
Cash flows from financing activities
Dividends paid	(10,316)	(10,271)	(9,836)
Proceeds from revolving credit facility borrowings	114,000		87,000
Repayment of revolving credit facility borrowings	(15,000)		(419,000)
Proceeds from issuance of senior notes, net	300,000		291,009
Repurchase of Convertible Notes	(232,963)
Repayments of short-term borrowings			(7,542)
Debt issuance costs paid	(8,854)		(14,959)
Proceeds from the issuance of common stock, net			64,835
Proceeds from the sale of PVG units, net (Note 3)		199,125	118,080
Distributions received from discontinued operations		11,218	42,279
Other, net	1,148	2,098
Net cash provided by financing activities from continuing operations	148,015	202,170	151,866
Cash flows from discontinued operations
Net cash provided by operating activities		77,759	158,214
Net cash used in investing activities		(18,112)	(80,506)
Net cash used in provided by financing activities		(59,647)	(77,708)
Net cash provided by discontinued operations
Net increase (decrease) in cash and cash equivalents	(113,399)	41,894	79,017
Cash and cash equivalents - beginning of period	120,911	79,017
Cash and cash equivalents - end of period	7,512	120,911	79,017
Cash paid for:
Interest (net of amounts capitalized)	44,589	43,531	34,640
Income taxes (net of refunds received)	$ 210	$ 28,184	$ 9,443