Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives			$ 3,439	$ 33,030
Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Interest expense—borrowings
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	$ 590	$ 634	1,199	1,272
Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps | Gains on derivative instruments, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(13)	(11)	(30)	(14)
Derivatives designated as hedging instruments | Interest rate risks | Interest rate risk
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	577	623	1,169	1,258
Derivatives not designated as hedging instruments | Currency exchange risks
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(1,384)	132	(1,101)	(9)
Derivatives not designated as hedging instruments | Currency exchange risks | Loans | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(5,307)	8,306	(2,816)	(11,853)
Derivatives not designated as hedging instruments | Currency exchange risks | Foreign exchange forwards | Gains on derivative instruments, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	3,923	(8,174)	1,715	11,844
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivative contracts | Gains on derivative instruments, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(269)	99	(690)	42
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign exchange forwards
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(65)	(15)	(2,065)	102
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign exchange forwards | Gains on derivative instruments, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	68	787	(5,586)	280
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign exchange forwards | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(133)	(802)	3,521	(178)
Derivatives not designated as hedging instruments | Other derivative instruments | Equity warrant assets | Gains on derivative instruments, net
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	$ 5,089	$ 23,616	$ 11,694	$ 43,894