SEGMENT INFORMATION (REVENUE GEOGRAPHY) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 2,462,817	$ 2,443,707	$ 2,273,062
Property, plant and equipment, gross	752,516	857,643	860,616
Other long-term assets	101,573	67,734	77,273
United States Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	1,710,716	1,738,053	1,570,791
Property, plant and equipment, gross	506,092	631,459	620,407
Other long-term assets	90,810	56,372	68,052
Philippines Asia Pacific India [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	477,455	457,526	476,395
Property, plant and equipment, gross	170,403	162,857	173,075
Other long-term assets	7,752	8,826	6,622
Europe Middle East Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	142,665	131,575	110,909
Property, plant and equipment, gross	30,290	21,435	19,594
Other long-term assets	2,021	1,306	1,735
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	131,981	116,553	114,967
Property, plant and equipment, gross	45,731	41,892	47,540
Other long-term assets	$ 990	$ 1,230	$ 864