Schedule of Repurchase Agreements Obligation by Type of Collateral Pledged (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 49,540	$ 40,929
Gross and Net Amounts of Liabilities Presented in the Statement of Financial Condition	65,692	55,946
Net Amount, Liabilities	2,019	791
Asset-backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	49,540
Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Gross and Net Amounts of Liabilities Presented in the Statement of Financial Condition	49,540	$ 40,929
Net Amount, Liabilities	0
Overnight and Continuous | Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Net Amount, Liabilities	0
Up to 30 Days | Asset-backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	5,148
Up to 30 Days | Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Net Amount, Liabilities	0
30 - 90 Days | Asset-backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	40,260
30 - 90 Days | Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Net Amount, Liabilities	0
Greater than 90 Days | Asset-backed Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	4,132
Greater than 90 Days | Repurchase Agreements
Assets Sold under Agreements to Repurchase [Line Items]
Net Amount, Liabilities	$ 0