Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 29,849	$ 32,193	$ 106,575	$ 77,365
Gains on equity warrant assets, net	37,561	34,141	107,213	72,393
Client investment fees	46,679	36,265	136,905	88,592
Foreign exchange fees	40,309	32,656	116,863	100,560
Credit card fees	30,158	24,121	86,431	68,739
Deposit service charges	22,482	19,588	65,496	56,081
Lending related fees	11,707	10,675	36,857	30,938
Letters of credit and standby letters of credit fees	10,842	8,409	31,205	24,938
Investment banking revenue	38,516	0	137,005	0
Commissions	12,275	0	40,812	0
Other	13,631	12,022	42,773	38,671
Total noninterest income	$ 294,009	$ 210,070	$ 908,135	$ 558,277