SEGMENT INFORMATION (SEGMENT FINANCIALS) (DETAILS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Revenue	$ 353,429	$ 305,105	$ 691,706	$ 617,515
Depreciation and amortization	16,258	17,221	30,758	34,950
Income (Loss) from Operations	21,589	16,228	48,079	33,981
Capital Expenditures	17,554	12,794	29,589	27,743
Total Assets	930,123		930,123		$ 846,304
Goodwill	166,874		166,874		129,648
Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	353,460			617,923
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	(31)			(408)
Customer Management Services
Segment Reporting Information [Line Items]
Net Revenue	269,056	212,807	521,135	440,728
Depreciation and amortization	13,146	11,879	24,388	24,133
Income (Loss) from Operations	14,075	8,339	34,671	23,934
Capital Expenditures	15,390	9,260
Total Assets	698,333		698,333		585,679
Goodwill	79,927		79,927		42,589
Customer Management Services | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	269,056	212,886	521,154	440,905
Customer Management Services | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0	(79)	(19)	(177)
Customer Growth Services
Segment Reporting Information [Line Items]
Net Revenue	32,403	36,893	66,061	70,412
Depreciation and amortization	754	1,639	1,532	3,382
Income (Loss) from Operations	2,321	3,482	4,731	3,977
Capital Expenditures	242	1,984
Total Assets	60,480		60,480		71,540
Goodwill	24,439		24,439		24,439
Customer Growth Services | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	32,403	36,893	66,061	70,412
Customer Growth Services | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	0			0
Customer Technology Services
Segment Reporting Information [Line Items]
Net Revenue	34,798	37,350	70,491	72,618
Depreciation and amortization	1,793	2,855	3,605	5,730
Income (Loss) from Operations	3,819	3,376	6,876	6,156
Capital Expenditures	1,645	1,280
Total Assets	102,302		102,302		115,537
Goodwill	40,839		40,839		41,500
Customer Technology Services | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	34,829	37,479	70,679	72,849
Customer Technology Services | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	(31)	(129)	(188)	(231)
Customer Strategy Services
Segment Reporting Information [Line Items]
Net Revenue	17,172	18,055	34,019	33,757
Depreciation and amortization	565	848	1,233	1,705
Income (Loss) from Operations	1,374	1,031	1,801	(86)
Capital Expenditures	277	270
Total Assets	69,008		69,008		73,548
Goodwill	21,669		21,669		$ 21,120
Customer Strategy Services | Operating Segments
Segment Reporting Information [Line Items]
Net Revenue	17,172	$ 18,055	$ 34,019	33,757
Customer Strategy Services | Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Revenue	$ 0			$ 0