Assets and Liabilities Related to Interest in Non-Consolidated VIEs and Maximum Exposure to Loss (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Investments	$ 517,284,000	$ 466,651,000
Accounts Receivable	14,593,000	11,726,000
Due from Affiliates	45,314,000	51,029,000
Total VIE Assets	577,191,000	529,406,000
Due to Affiliates	652,000	586,000
Accounts Payable, Accrued Expenses and Other Liabilities	122,000	88,000
Potential Clawback Obligation	74,676,000	73,450,000
Maximum Exposure to Loss	$ 652,641,000	$ 603,530,000