REVENUES (Schedule of Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 1,165,465	$ 1,210,941
Revenues from performance obligations satisfied in previous period	13,100	7,200
Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	1,161,039	1,207,255
Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	4,426	3,686
Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	981,526	1,074,979
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	176,324	130,505
Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	7,615	5,457
Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	259,130	278,360
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	242,736	270,665
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	173,432	189,191
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	170,318	202,380
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	140,209	111,258
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	179,640	159,087
Americas
Disaggregation of Revenue [Line Items]
Revenues	692,920	709,802
EMEA
Disaggregation of Revenue [Line Items]
Revenues	449,247	463,937
APAC
Disaggregation of Revenue [Line Items]
Revenues	23,298	26,810
CEE
Disaggregation of Revenue [Line Items]
Revenues	0	10,392
North America
Disaggregation of Revenue [Line Items]
Revenues	704,729	709,957
North America | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	700,384	707,034
North America | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	4,345	2,923
North America | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	605,696	644,628
North America | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	92,035	61,231
North America | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	6,998	4,098
North America | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	117,691	123,659
North America | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	124,292	143,850
North America | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	133,194	149,798
North America | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	106,692	116,158
North America | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	121,717	96,597
North America | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	101,143	79,895
North America | Americas
Disaggregation of Revenue [Line Items]
Revenues	668,182	683,553
North America | EMEA
Disaggregation of Revenue [Line Items]
Revenues	35,824	25,372
North America | APAC
Disaggregation of Revenue [Line Items]
Revenues	723	726
North America | CEE
Disaggregation of Revenue [Line Items]
Revenues	0	306
Europe
Disaggregation of Revenue [Line Items]
Revenues	460,736	493,147
Europe | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	460,655	492,397
Europe | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	81	750
Europe | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	375,830	425,598
Europe | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	84,289	66,203
Europe | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	617	1,346
Europe | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	141,439	153,055
Europe | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	118,444	123,608
Europe | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	40,238	38,682
Europe | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	63,626	86,108
Europe | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	18,492	14,526
Europe | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	78,497	77,168
Europe | Americas
Disaggregation of Revenue [Line Items]
Revenues	24,738	25,954
Europe | EMEA
Disaggregation of Revenue [Line Items]
Revenues	413,423	438,565
Europe | APAC
Disaggregation of Revenue [Line Items]
Revenues	22,575	26,084
Europe | CEE
Disaggregation of Revenue [Line Items]
Revenues	0	2,544
Russia
Disaggregation of Revenue [Line Items]
Revenues	$ 0	7,837
Russia | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues		7,824
Russia | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues		13
Russia | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues		4,753
Russia | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues		3,071
Russia | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues		13
Russia | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues		1,646
Russia | Financial Services
Disaggregation of Revenue [Line Items]
Revenues		3,207
Russia | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues		711
Russia | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues		114
Russia | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues		135
Russia | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues		2,024
Russia | Americas
Disaggregation of Revenue [Line Items]
Revenues		295
Russia | EMEA
Disaggregation of Revenue [Line Items]
Revenues		0
Russia | APAC
Disaggregation of Revenue [Line Items]
Revenues		0
Russia | CEE
Disaggregation of Revenue [Line Items]
Revenues		$ 7,542