Other Assets and Liabilities - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Loan portfolio payments held by servicer	$ 33,050	$ 122,666
Accrued interest receivable	31,323	37,161
Real estate debt and equity investments, at fair value	1,441	14,220
Prepaid expenses	325	890
Derivative assets	268	8,657
Prepaid taxes	206	525
Total	$ 66,613	$ 184,119