Reconciliation of Total Amounts of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Beginning Balance of Unrecognized Tax Benefits	$ 7,284	$ 5,088	$ 5,333
Additions based on tax positions related to the current year	2,618	2,318	241
Additions for tax positions of prior years	1,422	55
Reductions for tax positions of prior years	(481)		(486)
Reductions to tax positions resulting from a lapse of the applicable statute of limitations	(254)	(177)
Settlements with taxation authorities	(3,035)
Ending Balance of Unrecognized Tax Benefits	$ 7,554	$ 7,284	$ 5,088