ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Changes in AOCI (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Accumulated other comprehensive income (loss)
Balance at the beginning	$ 324,077
Balance at the end	330,147
Foreign Currency Translation
Accumulated other comprehensive income (loss)
Balance at the beginning	(8,603)
Other comprehensive income before reclassifications, net of tax	(1,871)
Other comprehensive income, net	(1,871)
Balance at the end	(10,474)
Unrealized Gain (Loss) on Interest Rate Hedge
Accumulated other comprehensive income (loss)
Balance at the beginning	(501)
Other comprehensive income before reclassifications, net of tax	1,382
Amounts reclassified out of AOCI, net of tax	213
Other comprehensive income, net	1,595
Balance at the end	1,094
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss)
Balance at the beginning	(9,104)
Other comprehensive income before reclassifications, net of tax	(489)
Amounts reclassified out of AOCI, net of tax	213
Other comprehensive income, net	(276)
Balance at the end	$ (9,380)