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	Dec. 31, 2010
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Beginning balance	$ 1,025	$ 1,022	$ 850
Additions based on tax positions related to prior year	39
Additions based on tax positions related to current year	5	3	172
Ending balance	$ 1,069	$ 1,025	$ 1,022