Schedule of Reconciliation of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits [Line Items]
Balance at January 1,	$ 7,403	$ 7,923	$ 5,754
Additions based on tax positions related to the current year	200	750	1,219
Additions for tax positions of prior years	386	419	2,076
Reductions for tax positions of prior years	(1,165)	(1,628)	(907)
Settlements		(61)	(219)
Balance at December 31,	$ 6,824	$ 7,403	$ 7,923