Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest rate risks | Derivatives designated as hedging instruments | Interest income—loans
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ (2,713)	$ 0	$ (3,224)	$ 0
Currency exchange risk | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(64)	410	(266)	(36)
Currency exchange risk | Derivatives not designated as hedging instruments | Revaluations of internal foreign currency instruments, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(8,724)	5,412	(5,183)	8,019
Currency exchange risk | Derivatives not designated as hedging instruments | Foreign exchange forward contracts, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	8,660	(5,002)	4,917	(8,055)
Other derivative instruments | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(14)	386	439	1,021
Other derivative instruments | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(1,123)	222	(2,619)	643
Other derivative instruments | Derivatives not designated as hedging instruments | Revaluations of internal foreign currency instruments, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(2,181)	(1,187)	(14,793)	3,718
Other derivative instruments | Derivatives not designated as hedging instruments | Foreign exchange forward contracts, net | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	2,167	1,573	15,232	(2,697)
Equity warrant assets
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives			(12,801)	24,462
Equity warrant assets | Derivatives not designated as hedging instruments | Gains on equity warrant assets, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ 37,561	$ 34,141	$ 107,213	$ 72,393