RESTRUCTURING COSTS - Restructuring Accrual (Details) - 2017 Strategic Restructuring Plan - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Liability beginning of period		$ 1,579,000
Charges	$ 0	0	$ (1,600,000)
Restructuring adjustment		(44,000)
Non-cash activity		(39,000)
Cash payments		(1,468,000)
Liability end of period	28,000	28,000	1,579,000
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Liability beginning of period		1,522,000
Charges		0
Restructuring adjustment		(44,000)
Non-cash activity		(10,000)
Cash payments		(1,468,000)
Liability end of period	0	0	1,522,000
Asset-Related Charges
Restructuring Reserve [Roll Forward]
Liability beginning of period		0
Charges		0
Restructuring adjustment		0
Non-cash activity		0
Cash payments		0
Liability end of period	0	0	0
Other
Restructuring Reserve [Roll Forward]
Liability beginning of period		57,000
Charges		0
Restructuring adjustment		0
Non-cash activity		(29,000)
Liability end of period	$ 28,000	$ 28,000	$ 57,000