Assets and Liabilities Related to Interest in Non-Consolidated VIEs and Maximum Exposure to Loss (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Investments	$ 774,579,000	$ 776,079,000
Accounts Receivable	28,729,000	125,316,000
Due from Affiliates	34,722,000	53,751,000
Total VIE Assets	838,030,000	955,146,000
Due to Affiliates	30,000	108,000
Accounts Payable, Accrued Expenses and Other Liabilities	244,000	124,000
Potential Clawback Obligation	260,198,000	206,725,000
Maximum Exposure to Loss	$ 1,098,502,000	$ 1,162,103,000