REVENUES (Schedule of Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Revenues	$ 1,400,061	$ 1,301,692
Revenues from performance obligations satisfied in previous period	24,000	12,600
Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	1,089,028	1,041,712
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	303,708	252,162
Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	7,325	7,818
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	350,200	313,965
Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	273,877	255,512
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	210,720	190,073
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	165,379	166,547
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	164,134	154,954
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	235,751	220,641
Americas
Disaggregation of Revenue [Line Items]
Revenues	799,469	780,285
EMEA
Disaggregation of Revenue [Line Items]
Revenues	576,012	497,115
APAC
Disaggregation of Revenue [Line Items]
Revenues	24,580	24,292
Americas
Disaggregation of Revenue [Line Items]
Revenues	795,396	777,168
Americas \| Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	630,569	641,173
Americas \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	158,094	129,378
Americas \| Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	6,733	6,617
Americas \| Financial Services
Disaggregation of Revenue [Line Items]
Revenues	165,446	149,350
Americas \| Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	122,190	114,675
Americas \| Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	132,822	135,662
Americas \| Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	115,897	113,220
Americas \| Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	125,033	125,979
Americas \| Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	134,008	138,282
Americas \| Americas
Disaggregation of Revenue [Line Items]
Revenues	748,501	742,052
Americas \| EMEA
Disaggregation of Revenue [Line Items]
Revenues	46,426	34,916
Americas \| APAC
Disaggregation of Revenue [Line Items]
Revenues	469	200
Europe
Disaggregation of Revenue [Line Items]
Revenues	604,665	524,524
Europe \| Time-and-materials
Disaggregation of Revenue [Line Items]
Revenues	458,459	400,539
Europe \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	145,614	122,784
Europe \| Licensing and other revenues
Disaggregation of Revenue [Line Items]
Revenues	592	1,201
Europe \| Financial Services
Disaggregation of Revenue [Line Items]
Revenues	184,754	164,615
Europe \| Consumer Goods, Retail & Travel
Disaggregation of Revenue [Line Items]
Revenues	151,687	140,837
Europe \| Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	77,898	54,411
Europe \| Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	49,482	53,327
Europe \| Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	39,101	28,975
Europe \| Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	101,743	82,359
Europe \| Americas
Disaggregation of Revenue [Line Items]
Revenues	50,968	38,233
Europe \| EMEA
Disaggregation of Revenue [Line Items]
Revenues	529,586	462,199
Europe \| APAC
Disaggregation of Revenue [Line Items]
Revenues	$ 24,111	$ 24,092