Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest rate risks | Derivatives designated as hedging instruments | Interest income—loans
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	$ (3)	$ 0
Currency exchange risk | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	581	(586)
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	1,050	2,926
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	(469)	(3,512)
Other derivative instruments | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(917)	539
Other derivative instruments | Derivatives not designated as hedging instruments | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	(365)	431
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	(13,571)	7,653
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	12,654	(7,114)
Equity warrant assets
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gains (losses) on derivatives	10,248	17,508
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	$ 21,305	$ 19,191