EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) - Housing loans $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum service period for employee housing program	3 years
Loan term (in years)	5 years
Interest rate on loan (as a percent)	7.50%
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans program lending limit	$ 10,000
Individual loan amount limit	$ 50