Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended		12 Months Ended		6 Months Ended		9 Months Ended
	May 31, 2008	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013 Employee Severance	Sep. 30, 2013 Employee Severance	Sep. 30, 2013 Letter of credit	Sep. 30, 2013 Clawback Liability	Sep. 30, 2013 Accrued expenses and other current liabilities	Sep. 30, 2013 Accrued expenses and other current liabilities Clawback Liability	Sep. 30, 2013 Other long-term liabilities	Sep. 30, 2013 Other long-term liabilities Clawback Liability	Sep. 30, 2013 Private equity funds [Member]
Commitment Contingencies And Guarantees [Line Items]
Company outstanding guarantees		$ 3,800,000					$ 2,400,000
Committed capital of private equity funds														100,000
Accrued expenses and other current liabilities									1,300,000
Accrued expenses and other current liabilities		3,540,000			2,601,000						1,000,000
Other long-term liabilities		3,814,000			3,921,000								300,000
Company's ownership in the funds									19.00%
Proceeds from sales of and distributions from companies and funds	6,400,000	2,603,000	14,526,000
Annual payments				650,000
Liability to former chairman and chief executive officer, current										800,000
Liability to former chairman and chief executive officer, non-current												2,700,000
Letter of credit under the credit facility								6,300,000
Letter of credit expiration date								Mar. 19, 2019
Severance charge						$ 900,000