Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
OPERATING ACTIVITIES:
Net income	$ 90,846	$ 68,328
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	129,475	90,304
Unrealized gain on derivatives	(1,147)	(1,453)
Deferred tax expense	56,872	36,260
Gain on disposition of assets	(158)	(10,418)
Stock compensation plans	7,026	7,476
Other	1,812	1,317
Changes in operating assets and liabilities increasing (decreasing) cash:
Accounts receivable	(11,407)	(17,787)
Accounts payable	(26,124)	2,046
Material and supplies inventory	(456)	(1)
Accrued liabilities	6,072	(2,650)
Contract advances	(779)	(353)
Other - net	7,478	4,698
Net cash provided by operating activities	259,510	177,767
INVESTING ACTIVITIES:
Capital expenditures	(343,755)	(217,544)
Producing property and other acquisitions	(9,791)	(94,030)
Proceeds from disposition of assets	1,604	33,985
Other - net	0	324
Net cash used in investing activities	(351,942)	(277,265)
FINANCING ACTIVITIES:
Borrowings under line of credit	164,500	166,400
Payments under line of credit	(327,500)	(66,400)
Proceeds from issuance of senior subordinated notes, net of offering costs	244,035	0
Proceeds from exercise of stock options	644	119
Book overdrafts	10,617	0
Net cash provided by financing activities	92,296	100,119
Net increase (decrease) in cash and cash equivalents	(136)	621
Cash and cash equivalents, beginning of period	1,359	1,140
Cash and cash equivalents, end of period	$ 1,223	$ 1,761