ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Summary of components of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		$ (17,833)	$ (10,115)
Change during the period:
Before-tax amount		(879)	(1)
Tax benefit		1	(1)
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]	250	168
Total activity for the period		(628)	166
Balance at June 30		(18,461)	(9,949)
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]	$ 250	$ 168
Total activity for the period		250	168
Balance at June 30		(15,996)	(9,592)
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		(3)	3
Tax benefit		$ 1	$ (1)
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]
Total activity for the period		$ (2)	$ 2
Balance at June 30		(100)	12
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Roll Forward]
Balance at December 31		(1,489)	(365)
Change during the period:
Before-tax amount		$ (876)	$ (4)
Tax benefit
Reclassification adjustment, net of taxes:
Amortization of net loss	[1]
Total activity for the period		$ (876)	$ (4)
Balance at June 30		$ (2,365)	$ (369)

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