Derivative Instruments and Other Hedging Activities - Schedule of Outstanding Derivative Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value of Derivatives
Derivative Asset	$ 34,172	$ 38,886
Derivative Liability	27,068	30,209
Notional Amount of Derivatives
Derivative assets	1,456,734	1,565,509
Derivative liabilities	1,729,550	1,528,184
Designated as Hedging Instruments
Fair Value of Derivatives
Derivative Asset	0	0
Derivative Liability	0	525
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	108,500
Designated as Hedging Instruments | Interest rate contracts
Notional Amount of Derivatives
Derivative assets	0	0
Derivative liabilities	108,500	108,500
Designated as Hedging Instruments | Interest rate contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	0	0
Designated as Hedging Instruments | Interest rate contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	0	525
Not Designated as Hedging Instruments
Notional Amount of Derivatives
Derivative assets	1,456,734	1,565,509
Derivative liabilities	1,621,050	1,419,684
Not Designated as Hedging Instruments | Other Assets
Fair Value of Derivatives
Derivative Asset	34,172	38,886
Not Designated as Hedging Instruments | Other Liabilities
Fair Value of Derivatives
Derivative Liability	27,068	29,684
Not Designated as Hedging Instruments | Interest rate contracts
Notional Amount of Derivatives
Derivative assets	1,065,894	1,033,955
Derivative liabilities	1,065,894	1,033,955
Not Designated as Hedging Instruments | Interest rate contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	20,982	20,719
Not Designated as Hedging Instruments | Interest rate contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	17,454	20,719
Not Designated as Hedging Instruments | Foreign exchange contracts
Notional Amount of Derivatives
Derivative assets	1,277	4,474
Derivative liabilities	1,277	4,474
Not Designated as Hedging Instruments | Foreign exchange contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	2	27
Not Designated as Hedging Instruments | Foreign exchange contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	2	26
Not Designated as Hedging Instruments | Forward sales contracts
Notional Amount of Derivatives
Derivative assets	32,438	229,181
Derivative liabilities	270,612	120,567
Not Designated as Hedging Instruments | Forward sales contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	145	6,014
Not Designated as Hedging Instruments | Forward sales contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	1,209	794
Not Designated as Hedging Instruments | Written and purchased options
Notional Amount of Derivatives
Derivative assets	348,417	289,115
Derivative liabilities	172,782	154,170
Not Designated as Hedging Instruments | Written and purchased options | Other Assets
Fair Value of Derivatives
Derivative Asset	13,043	12,125
Not Designated as Hedging Instruments | Written and purchased options | Other Liabilities
Fair Value of Derivatives
Derivative Liability	8,361	8,098
Not Designated as Hedging Instruments | Other contracts
Notional Amount of Derivatives
Derivative assets	8,708	8,784
Derivative liabilities	110,485	106,518
Not Designated as Hedging Instruments | Other contracts | Other Assets
Fair Value of Derivatives
Derivative Asset	0	1
Not Designated as Hedging Instruments | Other contracts | Other Liabilities
Fair Value of Derivatives
Derivative Liability	$ 42	$ 47