Schedule of Revenue and Income for Discontinued Operations (Detail) (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
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue		$ 180,802		$ 498,330
Income (loss) before income taxes		68,746	(37,568)	209,217
Provision for income taxes	1,543	(30,180)	15,222	(71,588)
Net income (loss)	1,543	38,566	(22,346)	137,629
Net income attributable to noncontrolling interest		21		(118)
Net income (loss) attributable to discontinued operations	$ 1,543	$ 38,587	$ (22,346)	$ 137,511
Earnings (loss) per share:
Basic	$ 0.01	$ 0.28	$ (0.17)	$ 1.01
Diluted	$ 0.01	$ 0.28	$ (0.16)	$ 0.99
Shares used in computing earnings per share:
Basic	135,968	136,176	133,919	136,632
Diluted	141,423	139,684	139,650	139,271