Derivative Financial Instruments - Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Fair Value, Net Total	$ 155,647	$ 144,346
Collateral	2,421	1,900
Net Exposure, Net	153,226	142,446
Derivatives designated as hedging instruments | Interest rate risks | Other assets | Interest rate swaps
Derivative [Line Items]
Notional or Contractual Amount	45,964	45,964
Fair value, Assets	1,324	2,768
Collateral	0	0
Net Exposure, Assets	1,324	2,768
Derivatives not designated as hedging instruments | Currency exchange risks
Derivative [Line Items]
Fair Value, Net exposure	1,100	140
Collateral	0	0
Net Exposure, Net	1,100	140
Derivatives not designated as hedging instruments | Currency exchange risks | Other assets | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	138,796	49,287
Fair value, Assets	1,676	809
Collateral	0	0
Net Exposure, Assets	1,676	809
Derivatives not designated as hedging instruments | Currency exchange risks | Other liability | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	53,051	6,586
Fair value, Liabilities	(576)	(669)
Collateral	0	0
Net Exposure, Liabilities	(576)	(669)
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivative contracts
Derivative [Line Items]
Fair Value, Net exposure	7,883	4,333
Collateral	2,421	1,900
Net Exposure, Net	5,462	2,433
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Equity warrant assets
Derivative [Line Items]
Notional or Contractual Amount	212,802	210,102
Fair value, Assets	145,340	137,105
Collateral	0	0
Net Exposure, Assets	145,340	137,105
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivative contracts | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	1,056,821	935,514
Fair value, Assets	44,636	29,722
Collateral	2,421	1,900
Net Exposure, Assets	42,215	27,822
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivative contracts | Client foreign currency options
Derivative [Line Items]
Notional or Contractual Amount	243,860	46,625
Fair value, Assets	2,750	706
Collateral	0	0
Net Exposure, Assets	2,750	706
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivative contracts | Client interest rate derivatives
Derivative [Line Items]
Notional or Contractual Amount	520,081	422,741
Fair value, Assets	8,759	3,973
Collateral	0	0
Net Exposure, Assets	8,759	3,973
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivative contracts | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	869,914	841,182
Fair value, Liabilities	(36,188)	(24,978)
Collateral	0	0
Net Exposure, Liabilities	(36,188)	(24,978)
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivative contracts | Client foreign currency options
Derivative [Line Items]
Notional or Contractual Amount	243,860	46,625
Fair value, Liabilities	(2,750)	(706)
Collateral	0	0
Net Exposure, Liabilities	(2,750)	(706)
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivative contracts | Client interest rate derivatives
Derivative [Line Items]
Notional or Contractual Amount	558,962	422,741
Fair value, Liabilities	(9,324)	(4,384)
Collateral	0	0
Net Exposure, Liabilities	$ (9,324)	$ (4,384)