Derivative Financial Instruments - Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Fair Value, Net Total	$ 137,313	$ 145,632
Collateral	470	12,668
Net Exposure, Net	136,843	132,964
Interest rate swaps
Derivative [Line Items]
Fair value, Assets	0	810
Foreign exchange forwards
Derivative [Line Items]
Fair value, Assets	76,882	57,644
Fair value, Liabilities	(71,201)	(44,285)
Client foreign currency options
Derivative [Line Items]
Fair value, Assets	4,961	10,383
Fair value, Liabilities	(4,969)	(10,383)
Client interest rate derivatives
Derivative [Line Items]
Fair value, Assets	11,655	10,110
Fair value, Liabilities	(11,765)	(9,770)
Derivatives designated as hedging instruments | Interest rate risks | Other assets
Derivative [Line Items]
Derivative, Notional Amount	0	45,964
Fair value, Assets	0	810
Collateral	0	89
Net Exposure, Assets	0	721
Derivatives not designated as hedging instruments | Foreign Exchange Contract
Derivative [Line Items]
Fair Value, Net exposure	(2,336)	2,089
Collateral	0	0
Net Exposure, Net	(2,336)	2,089
Derivatives not designated as hedging instruments | Foreign Exchange Contract | Other assets
Derivative [Line Items]
Derivative, Notional Amount	0	219,950
Fair value, Assets	0	3,057
Collateral	0	0
Net Exposure, Assets	0	3,057
Derivatives not designated as hedging instruments | Foreign Exchange Contract | Other liability
Derivative [Line Items]
Derivative, Notional Amount	293,721	54,338
Fair value, Liabilities	(2,336)	(968)
Collateral	0	0
Net Exposure, Liabilities	(2,336)	(968)
Derivatives not designated as hedging instruments | Other derivative instruments | Other derivative contracts
Derivative [Line Items]
Fair Value, Net exposure	7,899	11,610
Collateral	470	12,579
Net Exposure, Net	7,429	(969)
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets
Derivative [Line Items]
Net Exposure, Assets	131,750	131,123
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Other derivative contracts
Derivative [Line Items]
Derivative, Notional Amount	606,926	775,000
Fair value, Assets	4,961	10,383
Collateral	0	0
Net Exposure, Assets	4,961	10,383
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Client interest rate derivatives
Derivative [Line Items]
Derivative, Notional Amount	631,690	583,511
Fair value, Assets	11,655	10,110
Collateral	0	0
Net Exposure, Assets	11,655	10,110
Derivatives not designated as hedging instruments | Other derivative instruments | Other assets | Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	1,934,019	1,251,308
Fair value, Assets	76,882	54,587
Collateral	470	12,579
Net Exposure, Assets	76,412	42,008
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Other derivative contracts
Derivative [Line Items]
Derivative, Notional Amount	606,930	775,000
Fair value, Liabilities	(4,969)	(10,383)
Collateral	0	0
Net Exposure, Liabilities	(4,969)	(10,383)
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Client interest rate derivatives
Derivative [Line Items]
Derivative, Notional Amount	675,539	627,639
Fair value, Liabilities	(11,765)	(9,770)
Collateral	0	0
Net Exposure, Liabilities	(11,765)	(9,770)
Derivatives not designated as hedging instruments | Other derivative instruments | Other liability | Foreign Exchange Contract
Derivative [Line Items]
Derivative, Notional Amount	1,930,994	1,068,991
Fair value, Liabilities	(68,865)	(43,317)
Collateral	0	0
Net Exposure, Liabilities	$ (68,865)	$ (43,317)