Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other Income and Expenses [Abstract]
Gains on investment securities, net	$ 47,698	$ 36,114	$ 76,726	$ 45,172
Gains on equity warrant assets, net	48,347	19,061	69,652	38,252
Client investment fees	45,744	29,452	90,226	52,327
Foreign exchange fees	38,506	34,077	76,554	67,904
Credit card fees	28,790	22,926	56,273	44,618
Deposit service charges	22,075	18,794	43,014	36,493
Lending related fees	11,213	9,528	25,150	20,263
Letters of credit and standby letters of credit fees	11,009	8,347	20,363	16,529
Investment banking revenue	48,694	0	98,489	0
Commissions	14,429	0	28,537	0
Other	17,245	14,390	29,142	26,649
Total noninterest income	$ 333,750	$ 192,689	$ 614,126	$ 348,207