LOANS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,464,419	$ 2,485,613
Borrower's sustained repayment performance period	6 months
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Foreclosed property	$ 216	122
Total residential loans included in held for sale loans	4,800	13,400
Residential Real Estate \| Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Process of foreclosure	1,600	843
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	993,403	1,032,983
Acquired credit impaired	12,100
Certain loans acquired in transfer not accounted for as debt securities, note balance, net	16,600
Financing receivable not considered impaired at time of acquisition	981,300
Acquired Loans \| Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 544,512	$ 564,271

Represents the note balance amount of loans, considered impaired, at the time of acquisition.

No definition available.

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- Definition

Represents the carrying amount of loans, not considered impaired, at the time of acquisition.

+ References

No definition available.

+ Details

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- Definition

Represents the reasonable period of a borrower's sustained repayment performance for consideration of returning the loan to performing status.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82894507&loc=d3e13503-111538

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- Definition

Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4437-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5162-111524

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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- Definition

The face amount of loans that will be sold to other entities.

+ References

+ Details

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- Definition

The fair value of collateral received that was taken through foreclosure due to default by the original transferor in lieu of collection of the secured receivable.

+ References

+ Details

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