Other Assets and Liabilities - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Loan portfolio payments held by servicer	$ 138,883	$ 122,666
Accrued interest receivable	36,022	37,161
Real estate debt and equity investments, at fair value	22,442	14,220
Derivative assets	14,023	8,657
Prepaid expenses	593	890
Prepaid taxes	486	525
Total	$ 212,449	$ 184,119