SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated other comprehensive income (loss)
Stockholders' Equity Attributable to Parent, Beginning Balance	$ 677,222
Adjust funded status of pension plan, net of tax of $0.2 and $0.6 million for the years December 31, 2013 and 2014 respectively	(809)	$ (724)	$ (631)
Foreign currency translation adjustment	26	4	(259)
Stockholders' Equity Attributable to Parent, Ending Balance	680,299	677,222
Adjust funded status of pension plan, tax	700	600
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income (loss)
Stockholders' Equity Attributable to Parent, Beginning Balance	(2,921)	(2,202)
Adjust funded status of pension plan, net of tax of $0.2 and $0.6 million for the years December 31, 2013 and 2014 respectively	(809)	(723)
Foreign currency translation adjustment	26	4
Stockholders' Equity Attributable to Parent, Ending Balance	(3,704)	(2,921)	(2,202)
Projected Pension Benefit Obligation
Accumulated other comprehensive income (loss)
Stockholders' Equity Attributable to Parent, Beginning Balance	(2,672)	(1,949)
Adjust funded status of pension plan, net of tax of $0.2 and $0.6 million for the years December 31, 2013 and 2014 respectively	(809)	(723)
Stockholders' Equity Attributable to Parent, Ending Balance	(3,481)	(2,672)	(1,949)
Translation Adjustment
Accumulated other comprehensive income (loss)
Stockholders' Equity Attributable to Parent, Beginning Balance	(249)	(253)
Foreign currency translation adjustment	26	4
Stockholders' Equity Attributable to Parent, Ending Balance	$ (223)	$ (249)	$ (253)