ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Summary of components of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		$ (18,102)	$ (17,969)
Change during the period:
Before-tax amount		565	709
Tax benefit		7	1
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	405	380
Total activity for the period		977	1,090
Balance		(17,125)	(16,879)
Pension Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		(15,503)	(14,715)
Change during the period:
Before-tax amount		0	0
Tax benefit		0	0
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	405	380
Total activity for the period		405	380
Balance		(15,098)	(14,335)
Unrealized Gain (Loss) On Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		39	36
Change during the period:
Before-tax amount		(19)	(3)
Tax benefit		7	1
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	0	0
Total activity for the period		(12)	(2)
Balance		27	34
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance		(2,638)	(3,290)
Change during the period:
Before-tax amount		584	712
Tax benefit		0	0
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	0	0
Total activity for the period		584	712
Balance		$ (2,054)	$ (2,578)

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