ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Summary of components of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		$ (17,833)	$ (10,115)
Change during the period:
Before-tax amount		(1,520)	(710)
Tax benefit		17	21
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	376	253
Total activity for the period		(1,127)	(436)
Balance at September 30		(18,960)	(10,551)
Pension Adjustment
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		$ (16,246)	$ (9,760)
Change during the period:
Before-tax amount
Tax benefit
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	$ 376	$ 253
Total activity for the period		376	253
Balance at September 30		(15,870)	(9,507)
Unrealized Gain (Loss) On Securities
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		(98)	10
Change during the period:
Before-tax amount		(46)	(57)
Tax benefit		$ 17	$ 21
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]
Total activity for the period		$ (29)	$ (36)
Balance at September 30		(127)	(26)
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		(1,489)	(365)
Change during the period:
Before-tax amount		$ (1,474)	$ (653)
Tax benefit
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]
Total activity for the period		$ (1,474)	$ (653)
Balance at September 30		$ (2,963)	$ (1,018)

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