Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidated Statements of Operations [Abstract]
Revenues	$ 966,837	$ 384,997
Costs and expenses:
Cost of services (exclusive of items shown separately below)	546,767	217,022
Depreciation, depletion, amortization and accretion	102,596	55,824
General and administrative expenses	176,021	84,615
Income from operations	141,453	27,536
Other income (expense):
Interest expense, net	(29,806)	(12,152)
Earnings (losses) from equity-method investments, net	(287)	27
Income from continuing operations before income taxes	111,360	15,411
Income taxes	41,203	5,534
Net income from continuing operations	70,157	9,877
Discontinued operations, net of income tax	(16,237)	5,626
Net income	$ 53,920	$ 15,503
Earnings per share information:
Continuing operations	$ 0.56	$ 0.13
Discontinued operations	$ (0.13)	$ 0.07
Basic earnings per share	$ 0.43	$ 0.20
Continuing operations	$ 0.55	$ 0.12
Discontinued operations	$ (0.13)	$ 0.07
Diluted earnings per share	$ 0.42	$ 0.19
Weighted average common shares used in computing earnings per share:
Basic	125,542	79,021
Incremental common shares from stock based compensation	1,802	1,738
Diluted	127,344	80,759