ACQUISITIONS ASSETS ACQUIRED (TABLES) (Details) - USD ($) $ in Thousands	Apr. 01, 2022	Apr. 08, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Operating lease assets			$ 121,574	$ 92,431
Deferred tax assets.			100,206	62,551
Goodwill			808,988	807,845	$ 739,481
Operating lease liability - short-term			38,271	35,271
Accrued employee compensation and benefits			146,184	145,096
Operating lease liability - long-term			$ 96,809	$ 69,575
Faneuil
Business Acquisition [Line Items]
Accounts receivable.	$ 704
Prepaid Expenses	8,420
Other assets	2,572
Operating lease assets	17,778
Fixed Assets Acquired	5,622
Goodwill	75,902
Total assets acquired	172,308
Operating lease liability - short-term	3,129
Accrued employee compensation and benefits	202
Accrued expenses	2,763
Operating lease liability - long-term	14,092
Deferred revenue.	811
Other	8,891
Total liabilities assumed	29,888
Total purchase price	142,420
Faneuil | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets	$ 61,310
Avtex
Business Acquisition [Line Items]
Cash		$ 18,638
Accounts receivable.		22,214
Prepaid Expenses		26,389
Other assets		480
Operating lease assets		3,614
Income Taxes Receivable		93
Fixed Assets Acquired		3,162
Goodwill		378,882
Total assets acquired		587,742
Accounts payable		20,580
Operating lease liability - short-term		678
Accrued employee compensation and benefits		4,325
Accrued income taxes		332
Accrued expenses		250
Operating lease liability - long-term		2,936
Deferred tax liabilities		1,930
Deferred revenue.		56,765
Total liabilities assumed		87,796
Total purchase price		499,946
Avtex | Trade Names [Member]
Business Acquisition [Line Items]
Intangible assets		5,300
Avtex | Intellectual Property [Member]
Business Acquisition [Line Items]
Intangible assets		770
Avtex | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets		$ 128,200