Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Operations [Abstract]
Revenues	$ 1,179,665	$ 537,042	$ 3,389,821	$ 1,401,932
Costs and expenses:
Cost of services (exclusive of items shown separately below)	708,608	285,124	1,966,659	752,813
Depreciation, depletion, amortization and accretion	128,160	61,807	366,272	177,651
General and administrative expenses	163,458	93,813	496,998	272,243
Income from operations	179,439	96,298	559,892	199,225
Other income (expense):
Interest expense, net	(28,118)	(18,894)	(88,101)	(47,309)
Gains (Losses) on Extinguishment of Debt	(2,294)		(2,294)
Intercompany Interest Expense Net
Earnings Losses from Consolidated Subsidiaries
Earnings (losses) from equity-method investments, net		8,198	(287)	13,724
Gain loss from Equity method investment			17,880
Income from continuing operations before income taxes	149,027	85,602	487,090	165,640
Income taxes	55,140	30,803	180,223	59,589
Net income (loss) from continuing operations	93,887	54,799	306,867	106,051
Income (loss) from discontinued operations, net of tax		4,781	(17,207)	17,141
Net income	$ 93,887	$ 59,580	$ 289,660	$ 123,192
Earnings per share information:
Continuing operations	$ 0.60	$ 0.69	$ 2.09	$ 1.33
Discontinued operations		$ 0.06	$ (0.11)	$ 0.22
Basic earnings per share	$ 0.60	$ 0.75	$ 1.98	$ 1.55
Continuing operations	$ 0.59	$ 0.67	$ 2.07	$ 1.31
Discontinued operations		$ 0.06	$ (0.12)	$ 0.21
Diluted earnings per share	$ 0.59	$ 0.73	$ 1.95	$ 1.52
Weighted average common shares used in computing earnings per share:
Basic	157,153	79,836	146,611	79,537
Incremental common shares from stock based compensation	1,423	1,418	1,758	1,588
Diluted	158,576	81,254	148,369	81,125