Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Tenant Reimbursements	$ 19,200	$ 18,300
Client reimbursements	700,000	1,800,000
Long term receivables related to private equity and real estate capital advisory engagements	34,100,000		34,000,000
Installments period	3 years
Depreciation and amortization of property and equipment	Depreciation is computed using the straight-line method over the life of the assets. Amortization of leasehold improvements is computed using the straight-line method over the lesser of the life of the asset or the remaining term of the lease.
Aircraft
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)	7 years
Equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)	5 years
Furniture and Fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)	7 years
Leasehold Improvements
Significant Accounting Policies [Line Items]
Estimated useful lives of fixed assets (in years)	10 years
Description of estimated useful lives	Lesser of 10 years or the remaining lease term
Capital advisory engagements
Significant Accounting Policies [Line Items]
Interest income on long term receivables	$ 200,000	$ 100,000