Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Gains on investment securities, net									$ 420,752	$ 134,670	$ 88,094
Gains on equity warrant assets, net									237,428	138,078	89,142
Client investment fees									132,200	182,068	130,360
Foreign exchange fees									178,733	159,262	138,812
Credit card fees									97,737	118,719	94,072
Deposit service charges									90,336	89,200	76,097
Lending related fees									57,533	49,920	41,949
Letters of credit and standby letters of credit fees									46,659	42,669	34,600
Investment banking revenue									413,985	195,177	0
Commissions									66,640	56,346	0
Other									98,145	55,370	51,858
Noninterest income	$ 621,783	$ 547,583	$ 368,848	$ 301,934	$ 313,344	$ 294,009	$ 333,750	$ 280,376	$ 1,840,148	$ 1,221,479	$ 744,984