Income Taxes (Detail) - The provision for income tax expense (benefit) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 434	$ 32	$ (5,605)
State	211	(31)	27
Total current	645	1	(5,578)
Deferred:
Federal			1,476
State			139
Total deferred			1,615
Income tax expense (benefit)	$ 645	$ 1	$ (3,963)