SEGMENT INFORMATION (REVENUE GEOGRAPHY) (DETAILS) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net	$ 344,947	$ 312,796	$ 305,105	$ 312,410	$ 341,816	$ 309,195	$ 310,223	$ 325,521	$ 1,275,258	$ 1,286,755	$ 1,241,781
Property, plant and equipment, gross	677,318				660,081				677,318	660,081	628,351
Other long-term assets	47,520				42,486				47,520	42,486	36,658
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									693,023	679,959	603,297
Property, plant and equipment, gross	441,222				415,918				441,222	415,918	382,508
Other long-term assets	36,442				34,007				36,442	34,007	27,728
Philippines [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									351,853	343,013	348,339
Property, plant and equipment, gross	133,214				140,712				133,214	140,712	119,482
Other long-term assets	8,194				5,220				8,194	5,220	5,202
Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									122,347	147,267	172,270
Property, plant and equipment, gross	50,605				49,464				50,605	49,464	67,193
Other long-term assets	1,161				1,161				1,161	1,161	1,456
Europe Middle East Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									65,866	78,182	83,944
Property, plant and equipment, gross	8,805				14,567				8,805	14,567	13,367
Other long-term assets	1,099				811				1,099	811	692
Asia Pacific[ Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									28,219	32,554	28,294
Property, plant and equipment, gross	23,484				23,181				23,484	23,181	26,502
Other long-term assets	110				165				110	165	1,309
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Sales Revenue Services Net									13,950	5,780	5,637
Property, plant and equipment, gross	19,988				16,239				19,988	16,239	19,299
Other long-term assets	$ 514				$ 1,122				$ 514	$ 1,122	$ 271