Other Assets and Liabilities - Summary of Components of Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued dividends payable	$ 91,004	$ 83,702
Derivative liabilities	58,915	42,263
Accrued interest payable	20,548	24,831
Accrued management and incentive fees payable	19,158	20,159
Current expected credit loss reserve for unfunded loan commitments	173,549	0
Accounts payable and other liabilities	2,671	5,008
Total	202,327	175,963
Unfunded Loan Commitments [Member]
Current expected credit loss reserve for unfunded loan commitments	$ 10,031	$ 0