BORROWINGS (Additional Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Residential real estate loans and securities pledged as collateral for FHLB advances, carrying value	$ 370,000	$ 337,600
FHLB Stock owned	10,400
FHLB borrowing capacity, authorized	800,000
Line of Credit Facility, Current Borrowing Capacity	161,700
Commercial loans pledged as collateral for Federal Reserve Discount Window, carrying value	282,100
Federal Reserve borrowing capacity	220,500
Secured Debt	80,000
Federal Home Loan Bank, Advances, Premium	80,000
Securities Sold under Agreements to Repurchase	70,652	50,045	$ 69,622
Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Securities Sold under Agreements to Repurchase	$ 98,000	$ 98,000