REVENUES (Schedule of Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation of Revenue [Line Items]
Revenues	$ 1,414,767	$ 1,353,443	$ 2,814,828	$ 2,655,135
Revenues from performance obligations satisfied in previous period	15,900	15,200	26,100	14,500
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	1,103,908	1,087,394	2,192,936	2,129,107
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	305,492	257,999	609,200	510,160
Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	5,367	8,050	12,692	15,868
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	366,187	328,313	716,387	642,278
Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	274,254	268,050	548,131	523,562
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	202,015	204,671	412,735	394,744
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	169,078	156,505	333,212	311,459
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	166,731	170,393	332,110	336,940
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	236,502	225,511	472,253	446,152
Americas
Disaggregation of Revenue [Line Items]
Revenues	805,413	801,433	1,604,882	1,581,718
EMEA
Disaggregation of Revenue [Line Items]
Revenues	582,234	524,809	1,158,246	1,021,924
APAC
Disaggregation of Revenue [Line Items]
Revenues	27,120	27,201	51,700	51,493
Americas
Disaggregation of Revenue [Line Items]
Revenues	792,262	787,400	1,587,658	1,564,568
Americas \| Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	635,143	654,029	1,265,712	1,295,202
Americas \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	152,744	126,928	310,838	256,306
Americas \| Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	4,375	6,443	11,108	13,060
Americas \| Financial Services
Disaggregation of Revenue [Line Items]
Revenues	171,295	148,552	336,741	297,902
Americas \| Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	119,904	118,742	242,094	233,417
Americas \| Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	128,660	144,310	261,482	279,972
Americas \| Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	123,283	124,937	248,316	250,916
Americas \| Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	115,994	118,844	231,891	232,064
Americas \| Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	133,126	132,015	267,134	270,297
Americas \| Americas
Disaggregation of Revenue [Line Items]
Revenues	749,857	751,194	1,498,358	1,493,246
Americas \| EMEA
Disaggregation of Revenue [Line Items]
Revenues	41,467	35,906	87,893	70,822
Americas \| APAC
Disaggregation of Revenue [Line Items]
Revenues	938	300	1,407	500
Europe
Disaggregation of Revenue [Line Items]
Revenues	622,505	566,043	1,227,170	1,090,567
Europe \| Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	468,765	433,365	927,224	833,905
Europe \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	152,748	131,071	298,362	253,854
Europe \| Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	992	1,607	1,584	2,808
Europe \| Financial Services
Disaggregation of Revenue [Line Items]
Revenues	194,892	179,761	379,646	344,376
Europe \| Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	154,350	149,308	306,037	290,145
Europe \| Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	73,355	60,361	151,253	114,772
Europe \| Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	45,795	31,568	84,896	60,543
Europe \| Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	50,737	51,549	100,219	104,876
Europe \| Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	103,376	93,496	205,119	175,855
Europe \| Americas
Disaggregation of Revenue [Line Items]
Revenues	55,556	50,239	106,524	88,472
Europe \| EMEA
Disaggregation of Revenue [Line Items]
Revenues	540,767	488,903	1,070,353	951,102
Europe \| APAC
Disaggregation of Revenue [Line Items]
Revenues	$ 26,182	$ 26,901	$ 50,293	$ 50,993