Summary of Allowances (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ (29,561)	$ (42,246)
Charged to costs and expenses	(31,897)	(8,108)
Write-offs/recoveries	36,776	20,793
Balance at end of period	$ (24,682)	$ (29,561)