Other Assets and Liabilities - Summary of Unfunded Loan Commitment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
CECL reserve	$ 128,945	$ 172,100	$ 178,050	$ 112,694	$ 173,549		$ 0
(Decrease) Increase in CECL reserve	(43,155)	(1,449)	65,356	98,752
U.S. Loans [Member]
CECL reserve	17,673	44,534	61,404	64,861	42,995
(Decrease) Increase in CECL reserve	(26,861)	1,539	(3,457)	55,906
Non-U.S. Loans [Member]
CECL reserve	8,829	24,600	19,745	21,825	27,734
(Decrease) Increase in CECL reserve	(15,771)	(3,134)	(2,080)	18,194
Unfunded Loan Commitment [Member]
CECL reserve	4,037	11,021	15,002	22,536	10,031		0
(Decrease) Increase in CECL reserve	(6,984)	990	(7,534)	19,273
Unfunded Loan Commitment [Member] | U.S. Loans [Member]
CECL reserve	2,854	7,169	12,836	19,793	6,953		0
(Decrease) Increase in CECL reserve	(4,315)	216	(6,957)	16,992
Unfunded Loan Commitment [Member] | Non-U.S. Loans [Member]
CECL reserve	1,140	3,772	2,078	2,672	2,994		0
(Decrease) Increase in CECL reserve	(2,632)	778	(594)	2,219
Accounting Standards Update 2016-13 [Member]
CECL reserve						$ 13,942
Accounting Standards Update 2016-13 [Member] | U.S. Loans [Member]
CECL reserve						8,955
Accounting Standards Update 2016-13 [Member] | Non-U.S. Loans [Member]
CECL reserve						3,631
Accounting Standards Update 2016-13 [Member] | Unfunded Loan Commitment [Member]
CECL reserve	3,300					3,263
Accounting Standards Update 2016-13 [Member] | Unfunded Loan Commitment [Member] | U.S. Loans [Member]
CECL reserve						2,801
Accounting Standards Update 2016-13 [Member] | Unfunded Loan Commitment [Member] | Non-U.S. Loans [Member]
CECL reserve						453
Unique Loans [Member]
CECL reserve	32,782	33,305	27,240	26,008	33,159		0
(Decrease) Increase in CECL reserve	(523)	146	1,232	24,652
Unique Loans [Member] | Unfunded Loan Commitment [Member]
CECL reserve	43	80	88	71	84		0
(Decrease) Increase in CECL reserve	(37)	(4)	17	62
Unique Loans [Member] | Accounting Standards Update 2016-13 [Member]
CECL reserve						1,356
Unique Loans [Member] | Accounting Standards Update 2016-13 [Member] | Unfunded Loan Commitment [Member]
CECL reserve						9
Impaired Loans [Member]
CECL reserve	69,661	69,661	69,661		69,661		0
(Decrease) Increase in CECL reserve			69,661
Impaired Loans [Member] | Unfunded Loan Commitment [Member]
CECL reserve	0	0	0	0	$ 0		$ 0
(Decrease) Increase in CECL reserve	$ 0	$ 0	$ 0	$ 0
Impaired Loans [Member] | Accounting Standards Update 2016-13 [Member] | Unfunded Loan Commitment [Member]
CECL reserve						$ 0