FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investment securities available-for-sale
Available-for-sale investment securities	$ 3,335,795	$ 3,773,226
Derivative
Derivative assets	83,780	79,834
Derivative liabilities	(82,323)	(81,892)
U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	720,479	998,515
U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	274,866	768,849
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	266,799	351,662
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	1,258,747	997,396
Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	147,654	175,649
Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	11,477	62,393
Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	222,377	279,432
Corporate debt securities | Non-investment grade
Investment securities available-for-sale
Available-for-sale investment securities	9,173	9,642
Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	383,894	89,795
Other securities
Investment securities available-for-sale
Available-for-sale investment securities	40,329	39,893
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investment securities available-for-sale
Available-for-sale investment securities	751,470	1,034,150
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	720,479	998,515
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	0	4,514
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities	30,991	31,121
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investment securities available-for-sale
Available-for-sale investment securities	2,584,325	2,739,076
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign currency forward contracts
Derivative
Derivative assets	4,325	2,365
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps and options
Derivative
Derivative assets	67,578	67,215
Derivative liabilities	(65,131)	(67,325)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange contracts
Derivative
Derivative assets	11,874	10,254
Derivative liabilities	(11,213)	(9,350)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Credit risk participation agreements (“RPAs”)
Derivative
Derivative assets	3
Derivative liabilities	(3)	(4)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	(5,976)	(5,213)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	274,866	768,849
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	266,799	351,662
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	1,258,747	997,396
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	147,654	175,649
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	11,477	62,393
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	222,377	279,432
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities | Non-investment grade
Investment securities available-for-sale
Available-for-sale investment securities	9,173	9,642
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	383,894	85,281
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities	9,338	8,772
Fair Value, Measurements, Recurring | Fair Value Measurements
Investment securities available-for-sale
Available-for-sale investment securities	3,335,795	3,773,226
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign currency forward contracts
Derivative
Derivative assets	4,325	2,365
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps and options
Derivative
Derivative assets	67,578	67,215
Derivative liabilities	(65,131)	(67,325)
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign exchange contracts
Derivative
Derivative assets	11,874	10,254
Derivative liabilities	(11,213)	(9,350)
Fair Value, Measurements, Recurring | Fair Value Measurements | Credit risk participation agreements (“RPAs”)
Derivative
Derivative assets	3
Derivative liabilities	(3)	(4)
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	(5,976)	(5,213)
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	720,479	998,515
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	274,866	768,849
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	266,799	351,662
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Available-for-sale investment securities	1,258,747	997,396
Fair Value, Measurements, Recurring | Fair Value Measurements | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	147,654	175,649
Fair Value, Measurements, Recurring | Fair Value Measurements | Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	11,477	62,393
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	222,377	279,432
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities | Non-investment grade
Investment securities available-for-sale
Available-for-sale investment securities	9,173	9,642
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign bonds | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	383,894	89,795
Fair Value, Measurements, Recurring | Fair Value Measurements | Other securities
Investment securities available-for-sale
Available-for-sale investment securities	$ 40,329	$ 39,893