Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies [Line Items]
Rent expense	$ 2,704	$ 2,237	$ 2,652
Deferred rent balance	632	223
Operating facility leases expiration period description	Various expiration dates through January 2018
Income tax liabilities not expected to become due	12 months
Liabilities recorded for indemnification agreements	$ 0	$ 0