ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS), Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Components of accumulated other comprehensive loss [Roll Forward]
Balance	$ 521,033
Other comprehensive income	551	$ 1,251
Balance	542,301
AOCI Attributable to Parent [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance	(6,849)
Balance	(6,298)
Foreign Currency Translation Adjustment [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance	(6,707)
Other comprehensive income	541
Balance	(6,166)
Postretirement Benefit Plan [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance	(142)
Other comprehensive income	10
Balance	$ (132)