Other Assets - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Principal and interest payments held by servicer	$ 77,145	$ 123,160
Accrued interest receivable	36,901	37,161
Real estate debt and equity investments, at fair value	11,826	14,220
Prepaid expenses	828	890
Prepaid taxes	485	525
Other		8,163
Total	$ 127,185	$ 184,119