Expected Future Non-cancelable Sublease Proceeds (Detail) (USD $)	Dec. 31, 2011
Schedule of Operating Leases [Line Items]
2012	$ 3,250,000
2013	1,602,000
2014	1,607,000
2015	1,616,000
2016	1,276,000
Thereafter	3,159,000
Total sublease proceeds	$ 12,510,000