Schedule of Valuation And Qualifying Accounts (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]
Provision for doubtful accounts	$ 21,728,000	$ 13,708,000	$ 19,214,000
Allowance for Doubtful Accounts, Discontinued Operations
Valuation and Qualifying Accounts Disclosure [Line Items]
Provision for doubtful accounts	100,000	200,000	500,000
Provision for Estimated Revenue Adjustments	$ 200,000	$ 300,000	$ 500,000