SEGMENT INFORMATION (REVENUE GEOGRAPHY) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 2,443,707	$ 2,273,062	$ 1,949,248
Property, plant and equipment, gross	857,643	860,616	838,306
Other long-term assets	67,734	77,273	69,438
United States Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	1,738,053	1,570,791	1,364,812
Property, plant and equipment, gross	631,459	620,407	590,647
Other long-term assets	56,372	68,052	55,716
Philippines Asia Pacific India [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	457,526	476,395	407,325
Property, plant and equipment, gross	162,857	173,075	178,309
Other long-term assets	8,826	6,622	10,482
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	116,553	114,967	98,633
Property, plant and equipment, gross	41,892	47,540	46,307
Other long-term assets	1,230	864	912
Europe Middle East Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	131,575	110,909	78,478
Property, plant and equipment, gross	21,435	19,594	23,043
Other long-term assets	$ 1,306	$ 1,735	$ 2,328