Reconciliations of Total Amount of Gross Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Schedule of Unrecognized Tax Benefits [Line Items]
Gross unrecognized tax benefits at beginning of year	$ 2,467	$ 2,527
Increases in tax positions for prior years		11
Decreases in tax positions for prior years	(19)
Increases in tax positions for current year	4,608	992
Settlements	(1,044)	(291)
Lapse in statute of limitations	(593)	(772)
Gross unrecognized tax benefits at end of year	$ 5,419	$ 2,467