Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 189,837	$ 29,849	$ 270,760	$ 106,575
Gains on equity warrant assets, net	53,766	37,561	93,667	107,213
Client investment fees	31,914	46,679	107,192	136,905
Foreign exchange fees	43,881	40,309	127,642	116,863
Credit card fees	22,756	30,158	72,348	86,431
Deposit service charges	22,015	22,482	67,115	65,496
Lending related fees	13,562	11,707	37,851	36,857
Letters of credit and standby letters of credit fees	12,192	10,842	35,155	31,205
Investment banking revenue	92,181	38,516	280,551	137,005
Commissions	16,257	12,275	49,197	40,812
Other	49,222	13,631	76,887	42,773
Total noninterest income	$ 547,583	$ 294,009	$ 1,218,365	$ 908,135