Results of Operations Associated with Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010		Dec. 31, 2009
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	$ 3,700,789	$ 3,175,353		$ 2,242,840
Income (loss) from operations before income taxes	188,231	25,521		34,068
Gain on sale before income taxes	12,684	0		117,557
Total income from discontinued operations before taxes	200,915	25,521		151,625
Provision for income taxes	69,145	6,999		27,858
Income from discontinued operations	131,770	18,522	[1]	123,767	[1]
United States
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	3,700,789	3,175,353		2,117,186
Income (loss) from operations before income taxes	188,231	25,521		41,760
Gain on sale before income taxes	12,684	0		0
Ecuador
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	0	0		125,654
Income (loss) from operations before income taxes	0	0		(7,692)
Gain on sale before income taxes	$ 0	$ 0		$ 117,557

[1] Reclassified to conform to current presentation.