Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended						12 Months Ended	1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Aircraft	Dec. 31, 2012 Equipment	Dec. 31, 2012 Furniture and Fixtures	Dec. 31, 2012 Leasehold Improvements	Dec. 31, 2012 Deferred Compensation Plan	Dec. 31, 2011 Deferred Compensation Plan	Dec. 31, 2012 Restricted Stock [Member]	Jun. 30, 2011 Iridium
Significant Accounting Policies [Line Items]
Client reimbursements	$ 7,400,000	$ 6,500,000	$ 5,900,000
Cash on deposit with financial institutions	50,324,000	62,050,000	78,227,000	74,473,000
Carrying value of cash equivalents	4,500,000	2,100,000
Cash and cash equivalents, restricted from use	7,055,000	7,300,000							2,600,000	2,900,000
Bad debt expense	100,000	100,000
Long term receivables related to private equity and real estate capital advisory engagements	29,800,000	21,300,000
Installments period	3 years	3 years
Interest Income on Long Term Receivables	$ 1,200,000	$ 100,000	$ 100,000
Warrants exercise price												$ 11.50
Compensation expense amortization period/service period following the date of grant											5 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.
Estimated useful lives of fixed assets (in years)					7 years	5 years	7 years	10 years
Estimated useful lives of fixed assets, description								Lesser of 10 years or the remaining lease term