Aggregate Minimum Operating Lease Payments under New Operating Leases Entered (Detail) (USD $)	Mar. 31, 2013
Operating Leases
Remainder of 2013	$ 3,726,000
2014	4,243,000
2015	2,123,000
2016	1,967,000
2017	342,000
Total minimum lease payments	12,401,000
New Operating Leases Entered in 2013
Operating Leases
Remainder of 2013	293
2014	394
2015	394
2016	353
2017	353
Thereafter	93
Total minimum lease payments	$ 1,880