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 income (loss)	$ 98,821	$ 46,294	$ (39,330)
Plus (gain) loss from discontinued operations, net of taxes	(14,211)	181	254
Adjustments to reconcile net income (loss) to net cash provided by operation activities -
Depreciation, depletion, and amortization	221,230	162,572	166,108
Write-down of oil and gas properties			79,312
Accretion of asset retirement obligation	4,570	3,956	2,906
Deferred income taxes	48,995	32,881	(13,377)
Stock-based compensation expense	12,625	10,256	9,232
Debt retirement cost - cash and non-cash			3,961
Other	2,143	1,563	16,133
Change in assets and liabilities-
(Increase) decrease in accounts receivable	(12,625)	(6,691)	2,666
Increase in accounts payable and accrued liabilities	10,134	472	1,977
Increase (decrease) in income taxes payable	(73)	247	(204)
Increase (decrease) in accrued interest	1,449	7,265	(3,462)
Cash provided by operating activities - continuing operations	373,058	258,996	226,176
Cash used in operating activities - discontinued operations	(2)	(41)	(396)
Net Cash Provided by Operating Activities	373,056	258,955	225,780
Cash Flows from Investing Activities:
Additions to property and equipment	(505,332)	(353,648)	(215,370)
Proceeds from the sale of property and equipment	50,284	133	31,083
Acquisition of properties	0	0	0
Cash used in investing activities - continuing operations	(455,048)	(353,515)	(184,287)
Cash provided by investing activities - discontinued operations	5,000	5,000	5,000
Net Cash Used in Investing Activities	(450,048)	(348,515)	(179,287)
Cash Flows from Financing Activities:
Proceeds from long-term debt	247,890		221,375
Payments of long-term debt			(150,000)
Net payments of bank borrowings			(180,700)
Net proceeds from issuances of common stock	2,151	142,917	109,801
Purchase of treasury shares	(3,393)	(1,828)	(884)
Payments of debt retirement costs			(2,859)
Payments of debt issuance costs	(4,327)	(3,631)	(5,040)
Cash provided by (used in) financing activities - continuing operations	242,321	137,458	(8,307)
Cash provided by financing activities - discontinued operations	0	0	0
Net Cash provided by (used in) financing activities	242,321	137,458	(8,307)
Net Increase in Cash and Cash Equivalents	165,329	47,898	38,186
Cash and Cash Equivalents at Beginning of Year	86,367	38,469	283
Cash and Cash Equivalents at End of Year	251,696	86,367	38,469
Supplemental Disclosures of Cash Flows Information:
Cash paid during year for interest, net of amounts capitalized	32,078	24,622	32,885
Cash paid during year for income taxes	$ 1,770	$ 200	$ 233