FAIR VALUE DISCLOSURES - Summary of Financial Assets and Liabilities Measure at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets
Investment securities available-for-sale	$ 2,908,688
Derivative Asset	308,819	$ 112,607
Liabilities
Derivative liabilities	308,888	112,616
Fair Value, Measurements, Recurring
Assets
Investment securities available-for-sale	2,908,688	2,852,084
Derivative Asset		73,558
Total	3,217,666	2,964,814
Liabilities
Total	310,132	112,922
Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 1
Assets
Investment securities available-for-sale	104	100
Derivative Asset		0
Total	104	100
Liabilities
Total	0	0
Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 2
Assets
Investment securities available-for-sale	2,864,334	2,842,794
Derivative Asset		73,558
Total	3,173,312	2,955,524
Liabilities
Total	310,132	112,922
Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 3
Assets
Investment securities available-for-sale	44,250	9,190
Derivative Asset		0
Total	44,250	9,190
Liabilities
Total	0	0
Interest Rate Contract [Member] \| Fair Value, Measurements, Recurring
Assets
Derivative Asset	204,351
Liabilities
Derivative liabilities	205,505	73,750
Interest Rate Contract [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 1
Assets
Derivative Asset	0
Liabilities
Derivative liabilities	0	0
Interest Rate Contract [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 2
Assets
Derivative Asset	204,351
Liabilities
Derivative liabilities	205,505	73,750
Interest Rate Contract [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 3
Assets
Derivative Asset	0
Liabilities
Derivative liabilities	0	0
Foreign Exchange [Member] \| Fair Value, Measurements, Recurring
Assets
Derivative Asset	104,627	39,172
Liabilities
Derivative liabilities	104,627	39,172
Foreign Exchange [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 1
Assets
Derivative Asset	0	0
Liabilities
Derivative liabilities	0	0
Foreign Exchange [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 2
Assets
Derivative Asset	104,627	39,172
Liabilities
Derivative liabilities	104,627	39,172
Foreign Exchange [Member] \| Fair Value, Measurements, Recurring \| Fair Value Measurements Using Level 3
Assets
Derivative Asset	0	0
Liabilities
Derivative liabilities	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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