Other Assets and Liabilities - Summary Of Current Expected Credit Loss Reserve By Pool (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Current Expected Credit Loss Reserve	$ 112,694
Increase in current expected credit loss reserve	122,702
Current Expected Credit Loss Reserve	112,694
CECL reserve on held-to-maturity debt securities [Member]
Current Expected Credit Loss Reserve	0
Increase in current expected credit loss reserve	4,677
Current Expected Credit Loss Reserve	5,122
Accounting Standards Update 2016-13 [Member]
Current Expected Credit Loss Reserve	17,650
Accounting Standards Update 2016-13 [Member] | CECL reserve on held-to-maturity debt securities [Member]
Increase in current expected credit loss reserve	445
U.S. Loans [Member] | CECL reserve on held-to-maturity debt securities [Member]
Current Expected Credit Loss Reserve	0
Increase in current expected credit loss reserve	4,677
Current Expected Credit Loss Reserve	5,122
U.S. Loans [Member] | Accounting Standards Update 2016-13 [Member]
Current Expected Credit Loss Reserve	8,955
U.S. Loans [Member] | Accounting Standards Update 2016-13 [Member] | CECL reserve on held-to-maturity debt securities [Member]
Increase in current expected credit loss reserve	445
Non-US Loans [Member] | CECL reserve on held-to-maturity debt securities [Member]
Current Expected Credit Loss Reserve	0
Increase in current expected credit loss reserve	0
Current Expected Credit Loss Reserve	0
Non-US Loans [Member] | Accounting Standards Update 2016-13 [Member]
Current Expected Credit Loss Reserve	3,631
Non-US Loans [Member] | Accounting Standards Update 2016-13 [Member] | CECL reserve on held-to-maturity debt securities [Member]
Increase in current expected credit loss reserve	0
Unique Loans [Member] | CECL reserve on held-to-maturity debt securities [Member]
Increase in current expected credit loss reserve	0
Unique Loans [Member] | Accounting Standards Update 2016-13 [Member]
Current Expected Credit Loss Reserve	0
Current Expected Credit Loss Reserve	1,356
Unique Loans [Member] | Accounting Standards Update 2016-13 [Member] | CECL reserve on held-to-maturity debt securities [Member]
Increase in current expected credit loss reserve	$ 0