Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Consolidated Statements of Operations [Abstract]
Revenues	$ 4,568,068	$ 1,964,332	$ 1,563,043
Costs and expenses:
Cost of services (exclusive of items shown separately below)	2,689,473	1,046,409	848,492
Depreciation, depletion, amortization and accretion	509,281	244,915	208,097
General and administrative expenses	662,792	376,619	332,602
Income from operations	706,522	296,389	173,852
Other income (expense):
Interest expense, net	(117,682)	(72,994)	(56,480)
Interest expense, net	117,682	72,994	56,480
Interest income	3,170	6,226	5,135
Other income (expense)	853	(822)	825
Gain (loss) on early estinguishment of debt	(2,294)
Intercompany Interest Expense Net
Earnings Losses from Consolidated Subsidiaries
Earnings (losses) from equity-method investments, net	(287)	16,394	8,245
Gain on sale of equity-method investments	17,880
Income from continuing operations before income taxes	608,162	245,193	131,577
Income taxes	225,020	85,804	45,431
Net income (loss) from continuing operations	383,142	159,389	86,146
Income (loss) from discontinued operations, net of tax	(17,207)	(16,835)	(4,329)
Net income	$ 365,935	$ 142,554	$ 81,817
Earnings per share information:
Continuing operations, basic	$ 2.57	$ 2.00	$ 1.09
Discontinued operations	$ (0.12)	$ (0.21)	$ (0.05)
Basic earnings per share	$ 2.45	$ 1.79	$ 1.04
Continuing operations, diluted	$ 2.54	$ 1.97	$ 1.08
Discontinued operations	$ (0.12)	$ (0.21)	$ (0.05)
Diluted earnings per share	$ 2.42	$ 1.76	$ 1.03
Weighted average common shares used in computing earnings per share:
Basic	149,288	79,654	78,758
Incremental common shares from stock based compensation	1,081	1,271	840
Incremental common shares from restricted stock units	737	170	136
Diluted	151,106	81,095	79,734