Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 34,868	$ 47,698	$ 80,923	$ 76,726
Gains on equity warrant assets, net	26,506	48,347	39,901	69,652
Client investment fees	31,885	45,744	75,278	90,226
Foreign exchange fees	36,256	38,506	83,761	76,554
Credit card fees	21,288	28,790	49,592	56,273
Deposit service charges	20,511	22,075	45,100	43,014
Lending related fees	11,164	11,213	24,289	25,150
Letters of credit and standby letters of credit fees	11,421	11,009	22,963	20,363
Investment banking revenue	141,503	48,694	188,370	98,489
Commissions	16,918	14,429	32,940	28,537
Other	16,528	17,245	27,665	29,142
Total noninterest income	$ 368,848	$ 333,750	$ 670,782	$ 614,126