ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Summary of components of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	[1]	$ (18,746)
Change during the period:
Adoption of accounting standard (Note 2)		(356)
Reclassification adjustment, net of taxes:
Balance		(21,207)
Pension Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		(15,878)	$ (14,470)
Change during the period:
Before-tax amount		0	0
Adoption of accounting standard (Note 2)		(2,732)	0
Reclassification adjustment, net of taxes:
Amortization of net loss	[2]	173	173
Total activity for the period		(2,559)	173
Balance		(18,437)	(14,297)
Unrealized Gain (Loss) On Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance			15
Change during the period:
Before-tax amount			(15)
Tax benefit			0
Reclassification adjustment, net of taxes:
Amortization of net loss	[2]		0
Total activity for the period			(15)
Balance			0
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		(2,868)	(2,247)
Change during the period:
Before-tax amount		98	(481)
Tax benefit			0
Reclassification adjustment, net of taxes:
Amortization of net loss	[2]	0	0
Total activity for the period		98	(481)
Balance		(2,770)	(2,728)
Accumulated Other Comprehensive (Loss) Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		(18,746)	(16,702)
Change during the period:
Before-tax amount		98	(496)
Tax benefit			0
Adoption of accounting standard (Note 2)		(2,732)	(15)
Reclassification adjustment, net of taxes:
Amortization of net loss	[2]	173	173
Total activity for the period		(2,461)	(323)
Balance		$ (21,207)	$ (17,025)

[1] Note 1

[2] Reported as part of selling, general and administrative expenses.