SEGMENT INFORMATION (REVENUE GEOGRAPHY) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 392,515	$ 349,853	$ 786,871	$ 725,102
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	235,733	188,744	472,700	398,592
Philippines [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	91,401	85,442	184,580	174,647
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	25,054	27,224	49,190	57,722
Europe Middle East Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	15,610	18,469	31,651	34,440
Asia Pacific India[ Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	14,155	14,139	26,980	27,576
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 10,562	$ 15,835	$ 21,770	$ 32,125