Derivative Financial Instruments - Summary of Derivative Activity and Related Impact on Consolidated Statements of Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	$ (13,356)		$ (757)
Derivatives designated as hedging instruments | Interest rate risks | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(12)		60
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	639		634
Derivatives designated as hedging instruments | Interest rate risks | Interest Rate Risk
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	627		694
Derivatives not designated as hedging instruments | Currency exchange risks
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(51)		(864)
Derivatives not designated as hedging instruments | Currency exchange risks | Loans | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	978		(7,064)
Derivatives not designated as hedging instruments | Currency exchange risks | Foreign exchange forwards
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	(1,029)		6,200
Derivatives not designated as hedging instruments | Other derivative instruments | Foreign exchange forwards
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	302		49
Derivatives not designated as hedging instruments | Other derivative instruments | Equity warrant assets
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	25,373		3,505
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives	$ (467)	[1]	$ 478	[1]

[1] Primarily represents the change in fair value of loan conversion options.