ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS), Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Components of accumulated other comprehensive loss [Roll Forward]
Balance			$ 521,033
Other comprehensive income/(loss)	$ 2,708	$ (1,133)	3,259	$ 118
Balance	562,384		562,384
AOCI Attributable to Parent [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance			(6,849)
Balance	(3,590)		(3,590)
Foreign Currency Translation Adjustment [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance			(6,707)
Other comprehensive income/(loss)			3,238
Balance	(3,469)		(3,469)
Postretirement Benefit Plan [Member]
Components of accumulated other comprehensive loss [Roll Forward]
Balance			(142)
Other comprehensive income/(loss)			21
Balance	$ (121)		$ (121)