ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of Changes in Accumulated Other Comprehensive Loss Included Within Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			$ 457,468
Other comprehensive income (loss) before tax	$ 613	$ 3,386	(3,955)	$ 8,861
Tax (provision) benefit attributable to other comprehensive income (loss)	202	(1,065)	992	(2,295)
Balance, end of period	436,448		436,448
Foreign currency translation adjustments
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			(21,366)	(31,973)
Other comprehensive income (loss) before tax			(4,419)	10,406
Tax (provision) benefit attributable to other comprehensive income (loss)			1,108	(2,894)
Balance, end of period	(25,785)	(21,567)	(25,785)	(21,567)
Foreign currency hedge
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			3,246	5,048
Other comprehensive income (loss) before tax			464	(1,598)
Tax (provision) benefit attributable to other comprehensive income (loss)			(116)	610
Balance, end of period	3,710	3,450	3,710	3,450
Defined benefit pension plans
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			(7,221)	(10,518)
Other comprehensive income (loss) before tax			0	53
Tax (provision) benefit attributable to other comprehensive income (loss)			0	(11)
Balance, end of period	(7,221)	(10,465)	(7,221)	(10,465)
Tax provision
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			5,545	8,443
Tax (provision) benefit attributable to other comprehensive income (loss)			992	(2,295)
Balance, end of period	6,537	6,148	6,537	6,148
Accumulated other comprehensive loss
Accumulated Other Comprehensive Loss [Line Items]
Balance, beginning of period			(19,796)	(29,000)
Other comprehensive income (loss)			(2,963)	6,566
Balance, end of period	$ (22,759)	$ (22,434)	$ (22,759)	$ (22,434)