SEGMENT AND GEOGRAPHICAL REPORTING - Reconciliation of Operating Income to Consolidated Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating income for reportable segments, excluding amortization	$ 130,118	$ 130,865	$ 90,124
Adjustments for:
Amortization of intangibles	15,074	16,586	17,266
Total operating income	66,122	68,451	33,490
Interest expense	19,498	20,937	17,054
Other expenses (income), net	(45)	(1,192)	(456)
Total income before taxes	46,669	48,706	16,892
Operating Segments
Segment Reporting, Other Significant Reconciling Item [Line Items]
Operating income for reportable segments, excluding amortization	130,118	130,865	90,124
Segment Reconciling Items
Adjustments for:
Amortization of intangibles	15,074	16,586	17,266
Corporate
Adjustments for:
Corporate and other expense, net	$ 48,922	$ 45,828	$ 39,368