Noninterest Income - Summary of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Gains on investment securities, net									$ 134,670	$ 88,094	$ 64,603
Gains on equity warrant assets, net									138,078	89,142	54,555
Client investment fees									182,068	130,360	56,136
Foreign exchange fees									159,262	138,812	115,760
Credit card fees									118,719	94,072	76,543
Deposit service charges									89,200	76,097	58,715
Lending related fees									49,920	41,949	43,265
Letters of credit and standby letters of credit fees									42,669	34,600	28,544
Investment banking revenue									195,177	0	0
Commissions									56,346	0	0
Other									55,370	51,858	59,110
Noninterest income	$ 313,344	$ 294,009	$ 333,750	$ 280,376	$ 186,707	$ 210,070	$ 192,689	$ 155,518	$ 1,221,479	$ 744,984	$ 557,231