Secured Debt Agreements, Net - Summary of Asset-Specific Financings (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) SecurityLoan	Dec. 31, 2019 USD ($) SecurityLoan
Participating Mortgage Loans [Line Items]
Financing provided	2023-03	2023-03
Financing provided, Principal Balance	$ 9,367,270	$ 10,083,938
Collateral Assets [Member]
Participating Mortgage Loans [Line Items]
Count | SecurityLoan	4	4
LIBOR [Member] | Collateral Assets [Member]
Participating Mortgage Loans [Line Items]
Weighted Average Yield/Cost Rate	4.90%	4.90%
Asset-Specific Financings [Member]
Participating Mortgage Loans [Line Items]
Financing provided	2023-03	2023-03
Guarantee	$ 95,721	$ 97,930
Collateral assets, Book Value	434,409	417,820
Financing provided, Book Value	340,407	323,504
Collateral assets, Principal Balance	445,917	429,983
Financing provided, Principal Balance	$ 347,618	$ 330,879
Count | SecurityLoan	4	4
Asset-Specific Financings [Member] | LIBOR [Member]
Participating Mortgage Loans [Line Items]
Weighted Average Yield/Cost Rate	3.42%	3.42%