FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investment securities available-for-sale
Total available-for-sale investment securities	$ 3,773,226	$ 2,626,617
U.S. Treasury securities
Investment securities available-for-sale
Total available-for-sale investment securities	998,515	873,435
U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Total available-for-sale investment securities	768,849	311,024
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities
Investment securities available-for-sale
Total available-for-sale investment securities	351,662	141,420
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities
Investment securities available-for-sale
Total available-for-sale investment securities	997,396	791,088
Municipal securities
Investment securities available-for-sale
Total available-for-sale investment securities	175,649	250,448
Other residential mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	62,393	53,918
Other commercial mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities		34,053
Corporate debt securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	364,713	115,182
Corporate debt securities: | Non-investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	9,642	14,681
Other securities
Investment securities available-for-sale
Total available-for-sale investment securities	44,407	41,368
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investment securities available-for-sale
Total available-for-sale investment securities	1,034,150	905,792
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities
Investment securities available-for-sale
Total available-for-sale investment securities	998,515	873,435
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other securities
Investment securities available-for-sale
Total available-for-sale investment securities	35,635	32,357
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investment securities available-for-sale
Total available-for-sale investment securities	2,739,076	1,714,297
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign currency forward contracts
Derivative
Derivative assets	2,365
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	5,213	9,922
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange options
Derivative
Derivative assets		6,136
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate swaps and caps
Derivative
Derivative assets	67,215	41,534
Derivative liabilities	67,325	41,779
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange contracts
Derivative
Derivative assets	10,254	8,118
Derivative liabilities	9,350	9,163
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Credit risk participation agreements (“RPA”)
Derivative
Derivative liabilities	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
Total available-for-sale investment securities	768,849	311,024
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
Total available-for-sale investment securities	351,662	141,420
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
Total available-for-sale investment securities	997,396	791,088
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal securities
Investment securities available-for-sale
Total available-for-sale investment securities	175,649	250,448
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other residential mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	62,393	53,918
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other commercial mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities		34,053
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	364,713	115,182
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities: | Non-investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	9,642	8,153
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other securities
Investment securities available-for-sale
Total available-for-sale investment securities	8,772	9,011
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investment securities available-for-sale
Total available-for-sale investment securities	0	6,528
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Embedded derivative liabilities
Derivative
Derivative liabilities		3,392
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Corporate debt securities: | Non-investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	0	6,528
Fair Value, Measurements, Recurring | Fair Value Measurements
Investment securities available-for-sale
Total available-for-sale investment securities	3,773,226	2,626,617
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign currency forward contracts
Derivative
Derivative assets	2,365
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps on certificates of deposit
Derivative
Derivative liabilities	5,213	9,922
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign exchange options
Derivative
Derivative assets		6,136
Fair Value, Measurements, Recurring | Fair Value Measurements | Interest rate swaps and caps
Derivative
Derivative assets	67,215	41,534
Derivative liabilities	67,325	41,779
Fair Value, Measurements, Recurring | Fair Value Measurements | Foreign exchange contracts
Derivative
Derivative assets	10,254	8,118
Derivative liabilities	9,350	9,163
Fair Value, Measurements, Recurring | Fair Value Measurements | Credit risk participation agreements (“RPA”)
Derivative
Derivative liabilities	4
Fair Value, Measurements, Recurring | Fair Value Measurements | Embedded derivative liabilities
Derivative
Derivative liabilities		3,392
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. Treasury securities
Investment securities available-for-sale
Total available-for-sale investment securities	998,515	873,435
Fair Value, Measurements, Recurring | Fair Value Measurements | U.S. government agency and U.S. government sponsored enterprise debt securities
Investment securities available-for-sale
Total available-for-sale investment securities	768,849	311,024
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
Total available-for-sale investment securities	351,662	141,420
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
Total available-for-sale investment securities	997,396	791,088
Fair Value, Measurements, Recurring | Fair Value Measurements | Municipal securities
Investment securities available-for-sale
Total available-for-sale investment securities	175,649	250,448
Fair Value, Measurements, Recurring | Fair Value Measurements | Other residential mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	62,393	53,918
Fair Value, Measurements, Recurring | Fair Value Measurements | Other commercial mortgage-backed securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities		34,053
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities: | Investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	364,713	115,182
Fair Value, Measurements, Recurring | Fair Value Measurements | Corporate debt securities: | Non-investment grade
Investment securities available-for-sale
Total available-for-sale investment securities	9,642	14,681
Fair Value, Measurements, Recurring | Fair Value Measurements | Other securities
Investment securities available-for-sale
Total available-for-sale investment securities	44,407	41,368
Derivative instruments not designated as hedging instruments
Derivative
Derivative assets	77,469	55,788
Derivative liabilities	76,679	54,334
Derivative instruments not designated as hedging instruments | Foreign exchange options
Derivative
Derivative assets	0	6,136
Derivative liabilities	0	0
Derivative instruments not designated as hedging instruments | Foreign exchange contracts
Derivative
Derivative assets	10,254	8,118
Derivative liabilities	9,350	9,163
Derivative instruments not designated as hedging instruments | Credit risk participation agreements (“RPA”)
Derivative
Derivative assets	0	0
Derivative liabilities	4	0
Derivative instruments not designated as hedging instruments | Embedded derivative liabilities
Derivative
Derivative assets	0	0
Derivative liabilities	$ 0	$ 3,392