FAIR VALUE - RECURRING BASIS (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($) item	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Financial assets:
Available-for-sale debt securities	$ 417,983	$ 524,303
Mortgage loans held for sale, at fair value	4,496	5,761	$ 5,193	$ 11,662
Consumer loans held for sale	2,419	2,677	$ 3,679	$ 2,198
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	$ 2,746	$ 2,928
Mortgage Servicing Rights
Assets and Liabilities Measured on Recurring Basis
Number of tranches carried at fair value | item	0	0
U.S. Treasury securities and U.S. Government agencies
Financial assets:
Available-for-sale debt securities	$ 217,001	$ 307,592
Private label mortgage backed security
Financial assets:
Available-for-sale debt securities	4,120	4,449
Mortgage backed securities - residential
Financial assets:
Available-for-sale debt securities	100,238	106,374
Collateralized mortgage obligations
Financial assets:
Available-for-sale debt securities	82,745	87,163
Freddie Mac preferred stock
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	328	473
Community Reinvestment Act mutual fund
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,418	2,455
Corporate bonds
Financial assets:
Available-for-sale debt securities	9,979	15,125
Trust preferred security
Financial assets:
Available-for-sale debt securities	3,900	3,600
Fair Value, Inputs, Level 1
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,418	2,455
Fair Value, Inputs, Level 2
Financial assets:
Available-for-sale debt securities	409,963	516,727
Mortgage loans held for sale, at fair value	4,496	5,761
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	328	473
Fair Value, Inputs, Level 3
Financial assets:
Available-for-sale debt securities	8,020	8,049
Consumer loans held for sale	2,419	2,677
Recurring basis
Financial assets:
Available-for-sale debt securities	417,983	524,303
Mortgage loans held for sale, at fair value	4,496	5,761
Consumer loans held for sale	2,419	2,677
Rate lock loan commitments	443	310
Mandatory forward contracts	47
Interest rate swap agreements	1,494	312
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,746	2,928
Financial Liabilities:
Mandatory forward contracts		9
Interest rate swap agreements	1,360	403
Transfers between Level 1, 2 or 3	0	0
Recurring basis | U.S. Treasury securities and U.S. Government agencies
Financial assets:
Available-for-sale debt securities	217,001	307,592
Recurring basis | Private label mortgage backed security
Financial assets:
Available-for-sale debt securities	4,120	4,449
Recurring basis | Mortgage backed securities - residential
Financial assets:
Available-for-sale debt securities	100,238	106,374
Recurring basis | Collateralized mortgage obligations
Financial assets:
Available-for-sale debt securities	82,745	87,163
Recurring basis | Freddie Mac preferred stock
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	328	473
Recurring basis | Community Reinvestment Act mutual fund
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,418	2,455
Recurring basis | Corporate bonds
Financial assets:
Available-for-sale debt securities	9,979	15,125
Recurring basis | Trust preferred security
Financial assets:
Available-for-sale debt securities	3,900	3,600
Recurring basis | Fair Value, Inputs, Level 1
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,418	2,455
Recurring basis | Fair Value, Inputs, Level 1 | Community Reinvestment Act mutual fund
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	2,418	2,455
Recurring basis | Fair Value, Inputs, Level 2
Financial assets:
Available-for-sale debt securities	409,963	516,254
Mortgage loans held for sale, at fair value	4,496	5,761
Rate lock loan commitments	443	310
Mandatory forward contracts	47
Interest rate swap agreements	1,494	312
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	328	473
Financial Liabilities:
Mandatory forward contracts		9
Interest rate swap agreements	1,360	403
Recurring basis | Fair Value, Inputs, Level 2 | U.S. Treasury securities and U.S. Government agencies
Financial assets:
Available-for-sale debt securities	217,001	307,592
Recurring basis | Fair Value, Inputs, Level 2 | Mortgage backed securities - residential
Financial assets:
Available-for-sale debt securities	100,238	106,374
Recurring basis | Fair Value, Inputs, Level 2 | Collateralized mortgage obligations
Financial assets:
Available-for-sale debt securities	82,745	87,163
Recurring basis | Fair Value, Inputs, Level 2 | Freddie Mac preferred stock
Equity securities with readily determinable fair value:
Equity securities with readily determinable fair value	328	473
Recurring basis | Fair Value, Inputs, Level 2 | Corporate bonds
Financial assets:
Available-for-sale debt securities	9,979	15,125
Recurring basis | Fair Value, Inputs, Level 3
Financial assets:
Available-for-sale debt securities	8,020	8,049
Consumer loans held for sale	2,419	2,677
Recurring basis | Fair Value, Inputs, Level 3 | Private label mortgage backed security
Financial assets:
Available-for-sale debt securities	4,120	4,449
Recurring basis | Fair Value, Inputs, Level 3 | Trust preferred security
Financial assets:
Available-for-sale debt securities	$ 3,900	$ 3,600