INDEBTEDNESS (Schedule of Credit Agreement) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Revolving credit facility	$ 38,000	$ 42,000
Less: deferred financing costs, net of accumulated amortization of $1,577 and $1,529	(501)	(550)
Total borrowed	37,499	41,450
Line of Credit Facility, Remaining Borrowing Capacity	112,000	108,000
Accumulated Amortization, Deferred Finance Costs	$ 1,577	$ 1,529
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest margin	2.00%	2.25%
Actual interest rates	3.94%	3.88%