SEGMENT INFORMATION (SEGMENT FINANCIALS) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Revenue	$ 375,249	$ 338,277
Depreciation and amortization	17,924	14,500
Income (Loss) from Operations	24,941	26,490
Capital Expenditures	7,508	12,035
Total Assets	1,034,862		$ 1,078,736
Goodwill	205,632		206,694
Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	375,249
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0
Customer Management Services [Member]
Segment Reporting Information [Line Items]
Net Revenue	292,641
Depreciation and amortization	15,177
Income (Loss) from Operations	18,215
Capital Expenditures	7,353	8,579
Total Assets	824,472		869,594
Goodwill	118,336		119,497
Customer Management Services [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	292,641
Customer Management Services [Member] | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0
Customer Growth Services [Member]
Segment Reporting Information [Line Items]
Net Revenue	32,540
Depreciation and amortization	595
Income (Loss) from Operations	1,380
Capital Expenditures		120
Total Assets	46,092		41,036
Goodwill	24,439		24,439
Customer Growth Services [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	32,540
Customer Growth Services [Member] | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0
Customer Technology Services [Member]
Segment Reporting Information [Line Items]
Net Revenue	35,208
Depreciation and amortization	1,630
Income (Loss) from Operations	4,844
Capital Expenditures	31	3,200
Total Assets	101,379		100,351
Goodwill	40,839		40,839
Customer Technology Services [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	35,208
Customer Technology Services [Member] | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0
Customer Strategy Services [Member]
Segment Reporting Information [Line Items]
Net Revenue	14,860
Depreciation and amortization	522
Income (Loss) from Operations	502
Capital Expenditures	124	$ 136
Total Assets	62,919		67,755
Goodwill	22,018		$ 21,919
Customer Strategy Services [Member] | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	14,860
Customer Strategy Services [Member] | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	$ 0