Provision for Income Taxes (Benefit) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 34	$ (2,091)	$ (134)
State	118	(70)	275
Total	152	(2,161)	141
Deferred:
Federal	196	(52,450)	(18,084)
State	39	(1,047)	(5,906)
Total	235	(53,497)	(23,990)
Total provision (benefit) for income taxes	$ 387	$ (55,658)	$ (23,849)