ACCUMULATED OTHER COMPREHENSIVE INCOME - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net foreign currency translation adjustment	$ (891,000)	$ (2,982,000)	$ 5,404,000
Unrealized loss on cash flow hedge	(1,771,000)	0	0
Tax	372,000	0	0
Net of tax	(1,399,000)	0	0
Net change in postretirement benefit plan (see Note 15 for further information)
Prior service (credit)/cost and (gain)/loss arising during the period	199,000	522,000	(49,000)
Amortization of prior service credit/(cost)	74,000	74,000	74,000
Amortization of gain/(loss)	(46,000)	(8,000)	(15,000)
Total before tax	227,000	588,000	10,000
Tax	101,000	434,000	(207,000)
Net of tax	328,000	1,022,000	(197,000)
Other comprehensive (loss)/income	(1,962,000)	(1,960,000)	$ 5,207,000
Loss related to net investment hedge	262,000
Taxes on net investment hedge	$ 70,000	$ 0