Restructuring Costs - Summarization of Restructuring Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Employee Severance and Benefits		$ 525
Termination of Certain Office Leases	1,200	647
Other	353	686
Total Restructuring Costs	1,553	1,858
Included in Accounts Payable, Accrued Expenses and Other Liabilities, Net Related to Lease Payments and Other Costs Incurred But Not Yet Paid as of December 31,	$ 1,959	$ 1,574	$ 1,464