Reconciliation of Changes in Tax Positions (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]
Beginning unrecognized tax benefit	$ 1,109	$ 2,012	$ 2,728
Additions for tax positions of prior years		98
Reductions for tax positions of prior years
Lapse of Statute of Limitations	(1,011)	(1,001)	(716)
Ending unrecognized tax benefit	$ 98	$ 1,109	$ 2,012