Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Income Tax Contingency [Line Items]
Beginning Balance	$ 7,837	$ 5,509
Gross increases for tax positions of prior years	83	483
Gross decreases for tax positions of prior years
Gross increases for tax positions of current year	1,137	1,956
Decreases due to settlements	(1,994)
Decreases for lapse of statute of limitations		(111)
Ending Balance	$ 7,063	$ 7,837