DERIVATIVES - Summary of Derivative Financial Instruments and Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	$ 2,624,586	$ 1,674,080
Derivative Asset	33,286	12,682
Estimate Fair Value Loss	(33,278)	(12,687)
Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	20,800	15,400
Credit Risk Derivative Liabilities, at Fair Value		100
Fair Value Hedges \| Matched interest rate swaps \| Accrued interest and other liabilities
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	1,312,293	837,040
Derivative Asset	29,240	5,529
Estimate Fair Value Loss	(4,038)	(7,158)
Fair Value Hedges \| Matched interest rate swaps \| Accrued interest and other assets
Derivatives, Fair Value [Line Items]
Inerest-bearing deposit liability	1,312,293	837,040
Derivative Asset	4,046	7,153
Estimate Fair Value Loss	$ (29,240)	$ (5,529)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Fair value of credit risk derivative liability.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5708775-113959

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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No definition available.

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