LOANS AND ALLOWANCE FOR LOAN LOSSES (Composition of Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net unamortized loan origination costs	$ (958)	$ (963)
Loans	2,789,148	2,782,439	$ 2,645,139
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	860,533	858,369
Loans	860,533	858,369	819,639
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,169,533	1,164,023
Loans	1,169,533	1,164,023	1,096,475
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	378,015	373,400
Loans	378,015	373,400	333,607
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	320,642	323,378
Loans	320,642	323,378	322,826
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	18,011	18,149
Loans	18,011	18,149	16,669
HPFC Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	42,414	45,120
Loans	$ 42,414	$ 45,120	$ 55,923

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for 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 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=65890831&loc=d3e10152-111534

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

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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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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