SEGMENT INFORMATION (REVENUE GEOGRAPHY) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 395,507	$ 364,936	$ 1,182,378	$ 1,090,038
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	240,863	206,433	713,561	605,024
Philippines [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	89,876	85,272	274,456	259,919
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	24,454	26,351	73,645	84,073
Europe Middle East Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	15,187	16,112	46,838	50,552
Asia Pacific India[ Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	14,733	15,368	41,713	42,945
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 10,394	$ 15,400	$ 32,165	$ 47,525