Other Assets - Summary of Components of Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Principal and interest payments held by servicer	$ 123,160
Accrued interest receivable	37,161	$ 17,240
Real estate debt and equity investments, at fair value	14,220	49,017
Prepaid expenses	890	948
Prepaid taxes	525	534
Other	8,163	2,469
Total	$ 184,119	$ 70,208