QUARTERLY FINANCIAL DATA (UNAUDITED) (QUARTERLY FINANCIALS TABLE) (DETAILS) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
QUARTERLY FINANCIAL DATA (UNAUDITED) [ABSTRACT]
Sales Revenue Services Net	$ 426,623	$ 359,036	$ 353,429	$ 338,277	$ 344,947	$ 312,796	$ 305,105	$ 312,410	$ 1,477,365	$ 1,275,258	$ 1,286,755
Cost of services	(312,618)	(275,548)	(268,004)	(253,898)	(249,943)	(233,541)	(226,768)	(231,340)	(1,110,068)	(941,592)	(928,247)
Selling, general and administrative	(49,942)	(45,167)	(43,985)	(43,220)	(44,895)	(40,628)	(44,774)	(45,500)	(182,314)	(175,797)	(194,606)
Depreciation and amortization	(17,234)	(16,515)	(16,258)	(14,500)	(16,914)	(16,811)	(17,221)	(17,729)	(64,507)	(68,675)	(63,808)
Restructuring charges, net	(4,897)	(6,006)	(3,593)	(169)	(502)	(3,688)	(114)	(88)	(14,665)	(4,392)	(1,814)
Impairment losses	(5,322)	0	0	0	(26,448)	(5,602)	0	0	(5,322)	(32,050)	(8,100)
Income from operations	36,610	15,800	21,589	26,490	6,245	12,526	16,228	17,753	100,489	52,752	90,180
Other income (expense)	(8,318)	1,846	(4,198)	(932)	290	(690)	(734)	(1,320)	(11,602)	(2,454)	(4,291)
Benefit from (provision for) income taxes	(69,016)	(2,071)	(1,597)	(5,391)	(6,196)	813	(2,952)	(4,528)	(78,075)	(12,863)	(20,004)
Net income attributable to noncontrolling interest	(728)	(806)	(1,100)	(922)	(953)	(1,198)	(926)	(680)	(3,556)	(3,757)	(4,219)
Net income (loss) attributable to TeleTech stockholders	$ (41,452)	$ 14,769	$ 14,694	$ 19,245	$ (614)	$ 11,451	$ 11,616	$ 11,225	$ 7,256	$ 33,678	$ 61,666
Weighted average shares outstanding
Basic	45,856	45,838	45,662	45,950	46,386	47,081	47,873	48,368	45,826	47,423	48,370
Diluted	46,461	46,367	46,150	46,315	46,677	47,315	48,221	48,746	46,382	47,736	49,011
Net income per share attributable to TeleTech stockholders
Basic	$ (0.90)	$ 0.32	$ 0.32	$ 0.42	$ (0.01)	$ 0.24	$ 0.24	$ 0.23	$ 0.16	$ 0.71	$ 1.27
Diluted	$ (0.89)	$ 0.32	$ 0.32	$ 0.42	$ (0.01)	$ 0.24	$ 0.24	$ 0.23	$ 0.16	$ 0.71	$ 1.26