ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Changes in accumulated other comprehensive income (loss) [Abstract]
Net foreign currency translation adjustment	$ (215,000)		$ (2,911,000)		$ (1,304,000)	$ (1,548,000)
Unrealized loss on cash flow hedge	(1,706,000)		0		(1,706,000)	0
Tax	407,000		0		407,000	0
Net of tax	(1,299,000)		0		(1,299,000)	0
Net change in postretirement benefit plan (see Note 15 for further information)
Amortization of prior service cost	18,000		17,000		36,000	35,000
Amortization of gain	(11,000)		(1,000)		(22,000)	(2,000)
Total before tax	7,000		16,000		14,000	33,000
Tax	(1,000)		0		(3,000)	(4,000)
Net of tax	6,000		16,000		11,000	29,000
Other comprehensive loss	(1,508,000)	$ (1,084,000)	(2,895,000)	$ 1,376,000	(2,592,000)	(1,519,000)
Loss related to net investment hedge	$ 2,911,000		$ 0		$ 2,911,000	$ 0