Derivative Financial Instruments - Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Fair Value, Net Total	$ 129,130	$ 126,879
Net Exposure, Net	126,593	119,098
Collateral	2,537	7,781
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	3,828	4,609
Net Exposure, Assets	3,828	1,639
Collateral	0	2,970
Derivatives not designated as hedging instruments | Currency exchange risks
Derivative [Line Items]
Fair Value, Net exposure	(25)	4,561
Net Exposure, Net	(25)	2,120
Collateral	0	2,441
Derivatives not designated as hedging instruments | Currency exchange risks | Other assets | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	121,987	200,957
Fair Value, Assets	419	5,050
Net Exposure, Assets	419	2,609
Collateral	0	2,441
Derivatives not designated as hedging instruments | Currency exchange risks | Other liability | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	2,224	6,226
Fair value, Liabilities	(444)	(489)
Net Exposure, Liabilities	(444)	(489)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivatives
Derivative [Line Items]
Fair Value, Net exposure	2,823	1,105
Net Exposure, Net	286	(1,265)
Collateral	2,537	2,370
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Equity warrant assets
Derivative [Line Items]
Notional or Contractual Amount	203,103	197,878
Fair Value, Assets	122,504	116,604
Net Exposure, Assets	122,504	116,604
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivatives | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	831,111	801,487
Fair Value, Assets	32,802	28,954
Net Exposure, Assets	30,265	26,584
Collateral	2,537	2,370
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivatives | Client foreign currency options
Derivative [Line Items]
Notional or Contractual Amount	41,917	34,926
Fair Value, Assets	765	227
Net Exposure, Assets	765	227
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivatives | Client interest rate derivatives
Derivative [Line Items]
Notional or Contractual Amount	370,799	387,410
Fair Value, Assets	2,087	2,546
Net Exposure, Assets	2,087	2,546
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivatives | Foreign exchange forwards
Derivative [Line Items]
Notional or Contractual Amount	716,529	774,355
Fair value, Liabilities	(29,819)	(27,647)
Net Exposure, Liabilities	(29,819)	(27,647)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivatives | Client foreign currency options
Derivative [Line Items]
Notional or Contractual Amount	41,917	34,926
Fair value, Liabilities	(765)	(227)
Net Exposure, Liabilities	(765)	(227)
Collateral	0	0
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivatives | Client interest rate derivatives
Derivative [Line Items]
Notional or Contractual Amount	370,799	387,410
Fair value, Liabilities	(2,247)	(2,748)
Net Exposure, Liabilities	(2,247)	(2,748)
Collateral	$ 0	$ 0