FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Investment securities available-for-sale
Available-for-sale investment securities	$ 3,240,332	$ 3,773,226
U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	488,560	998,515
U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Available-for-sale investment securities	703,929	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	308,364	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	1,058,901	997,396
Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	153,903	175,649
Non-agency residential mortgage-backed securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	55,975	62,393
Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	416,864	364,713
Corporate debt securities | Non-investment grade
Investment securities available-for-sale
Available-for-sale investment securities	8,408	9,642
Other securities
Investment securities available-for-sale
Available-for-sale investment securities	45,428	44,407
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investment securities available-for-sale
Available-for-sale investment securities	525,056	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	488,560	998,515
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	36,496	35,635
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investment securities available-for-sale
Available-for-sale investment securities	2,715,276	2,739,076
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign currency forward contracts
Derivative
Derivative assets	1,732	2,365
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps and options
Derivative
Derivative assets	157,035	67,215
Derivative liabilities	(159,776)	(67,325)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange contracts
Derivative
Derivative assets	10,078	10,254
Derivative liabilities	(8,634)	(9,350)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	(810)	(5,213)
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Credit risk participation agreements (“RPAs”)
Derivative
Derivative liabilities	(12)	(4)
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	703,929	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	308,364	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	1,058,901	997,396
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	153,903	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	55,975	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	416,864	364,713
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	8,408	9,642
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other securities
Investment securities available-for-sale
Available-for-sale investment securities	8,932	8,772
Fair Value, Measurements, Recurring | Fair Value Measurements
Investment securities available-for-sale
Available-for-sale investment securities	3,240,332	3,773,226
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign currency forward contracts
Derivative
Derivative assets	1,732	2,365
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps and options
Derivative
Derivative assets	157,035	67,215
Derivative liabilities	(159,776)	(67,325)
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign exchange contracts
Derivative
Derivative assets	10,078	10,254
Derivative liabilities	(8,634)	(9,350)
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	(810)	(5,213)
Fair Value, Measurements, Recurring | Fair Value Measurements | Credit risk participation agreements (“RPAs”)
Derivative
Derivative liabilities	(12)	(4)
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. Treasury securities
Investment securities available-for-sale
Available-for-sale investment securities	488,560	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	703,929	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	308,364	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	1,058,901	997,396
Fair Value, Measurements, Recurring | Fair Value Measurements | Municipal securities
Investment securities available-for-sale
Available-for-sale investment securities	153,903	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	55,975	62,393
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities | Investment grade
Investment securities available-for-sale
Available-for-sale investment securities	416,864	364,713
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities | Non-investment grade
Investment securities available-for-sale
Available-for-sale investment securities	8,408	9,642
Fair Value, Measurements, Recurring | Fair Value Measurements | Other securities
Investment securities available-for-sale
Available-for-sale investment securities	$ 45,428	$ 44,407