REVENUES (Schedule of Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 1,146,597	$ 1,170,206	$ 2,312,062	$ 2,381,147
Revenues from performance obligations satisfied in previous period	10,400	3,500	15,400	5,600
Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	1,141,430	1,166,309	2,302,469	2,373,564
Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	5,167	3,897	9,593	7,583
Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	943,621	1,028,020	1,925,147	2,102,999
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	195,651	135,353	371,975	265,858
Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	7,325	6,833	14,940	12,290
Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	252,327	273,459	511,457	551,819
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	244,369	258,968	487,105	529,633
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	168,822	175,218	342,254	364,409
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	165,762	189,684	336,080	392,064
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	140,084	114,441	280,293	225,699
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	175,233	158,436	354,873	317,523
Americas
Disaggregation of Revenue [Line Items]
Revenues	691,199	679,087	1,384,119	1,388,889
EMEA
Disaggregation of Revenue [Line Items]
Revenues	431,321	459,085	880,568	923,022
APAC
Disaggregation of Revenue [Line Items]
Revenues	24,077	24,219	47,375	51,029
CEE
Disaggregation of Revenue [Line Items]
Revenues	0	7,815	0	18,207
North America
Disaggregation of Revenue [Line Items]
Revenues	698,629	680,071	1,403,358	1,390,028
North America | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	695,853	676,637	1,396,237	1,383,671
North America | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	2,776	3,434	7,121	6,357
North America | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	592,045	606,766	1,197,741	1,251,394
North America | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	102,328	67,273	194,363	128,504
North America | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	4,256	6,032	11,254	10,130
North America | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	113,999	120,038	231,690	243,697
North America | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	123,369	135,178	247,661	279,028
North America | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	128,261	135,755	261,455	285,553
North America | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	110,789	106,357	217,481	222,515
North America | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	120,607	99,966	242,324	196,563
North America | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	101,604	82,777	202,747	162,672
North America | Americas
Disaggregation of Revenue [Line Items]
Revenues	665,178	653,601	1,333,360	1,337,154
North America | EMEA
Disaggregation of Revenue [Line Items]
Revenues	32,717	25,629	68,541	51,001
North America | APAC
Disaggregation of Revenue [Line Items]
Revenues	734	649	1,457	1,375
North America | CEE
Disaggregation of Revenue [Line Items]
Revenues	0	192	0	498
Europe
Disaggregation of Revenue [Line Items]
Revenues	447,968	483,442	908,704	976,589
Europe | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	445,577	482,999	906,232	975,396
Europe | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	2,391	443	2,472	1,193
Europe | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	351,576	416,194	727,406	841,792
Europe | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	93,323	66,468	177,612	132,671
Europe | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	3,069	780	3,686	2,126
Europe | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	138,328	151,639	279,767	304,694
Europe | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	121,000	120,361	239,444	243,969
Europe | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	40,561	38,910	80,799	77,592
Europe | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	54,973	83,260	118,599	169,368
Europe | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	19,477	14,454	37,969	28,980
Europe | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	73,629	74,818	152,126	151,986
Europe | Americas
Disaggregation of Revenue [Line Items]
Revenues	26,021	25,150	50,759	51,104
Europe | EMEA
Disaggregation of Revenue [Line Items]
Revenues	398,604	433,456	812,027	872,021
Europe | APAC
Disaggregation of Revenue [Line Items]
Revenues	23,343	23,570	45,918	49,654
Europe | CEE
Disaggregation of Revenue [Line Items]
Revenues	0	1,266	0	3,810
Russia
Disaggregation of Revenue [Line Items]
Revenues	$ 0	6,693	$ 0	14,530
Russia | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues		6,673		14,497
Russia | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues		20		33
Russia | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues		5,060		9,813
Russia | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues		1,612		4,683
Russia | Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues		21		34
Russia | Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues		1,782		3,428
Russia | Financial Services
Disaggregation of Revenue [Line Items]
Revenues		3,429		6,636
Russia | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues		553		1,264
Russia | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues		67		181
Russia | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues		21		156
Russia | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues		841		2,865
Russia | Americas
Disaggregation of Revenue [Line Items]
Revenues		336		631
Russia | EMEA
Disaggregation of Revenue [Line Items]
Revenues		0		0
Russia | APAC
Disaggregation of Revenue [Line Items]
Revenues		0		0
Russia | CEE
Disaggregation of Revenue [Line Items]
Revenues		$ 6,357		$ 13,899