Securitized Debt - Callable Debt (Detail) - Securitized Loans $ in Thousands	Mar. 31, 2017 USD ($)
Debt Instrument, Redemption [Line Items]
2017	$ 1,162,931
2018	1,130,809
2019	457,005
2020	3,903,177
2021	3,290,623
Total	$ 9,944,545