Supplemental Disclosure of Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Cash Flow, Supplemental [Line Items]
Interest payments	$ 54,516	$ 37,083	$ 43,010
Income tax payments	$ 64,389	$ 55,991	$ 8,719