Reconciliation of Total Amounts of Gross Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Unrecognized Tax Benefits [Line Items]
Balance at beginning of period	$ 11,669	$ 12,505	$ 13,135
Gross increases-tax positions in prior years	352	564	910
Gross decreases-tax positions in prior years	(273)	(1,061)	(493)
Gross increases-tax positions in current year	42	40	64
Settlements	(252)	(111)	(1,111)
Lapse of statute of limitations	(4,441)	(268)
Balance at end of period	$ 7,097	$ 11,669	$ 12,505