ACQUISITIONS (Details) $ in Thousands				3 Months Ended		12 Months Ended
	Apr. 01, 2024 USD ($)	Feb. 01, 2024 USD ($) installment	Mar. 01, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Acquisitions
Number of installments of contingent consideration payments | installment		4
Goodwill				$ 849,790	$ 842,936	$ 845,396
Estimated amount	$ 1,500
Cash consideration				100
Carrying value of other intangibles				100
Certain assets Of creative plan design limited
Acquisitions
Total consideration		$ 5,900
Term of revenue target for contingent consideration arrangements		3 years
Fair value of contingent consideration at acquisition date		$ 3,000
Certain assets Of creative plan design limited | Measurement input discount rate | Minimum | Level 3
Acquisitions
Contingent consideration, measurement input		15.1
Certain assets Of creative plan design limited | Measurement input discount rate | Maximum | Level 3
Acquisitions
Contingent consideration, measurement input		19.1
Certain assets Of creative plan design limited | Measurement input revenue multiple | Level 3
Acquisitions
Contingent consideration, measurement input		82
Certain assets Of creative plan design limited
Acquisitions
Purchase price of acquisition				8,927
Minimum contingent consideration liability that could be paid		$ 0
Maximum contingent consideration liability that could be paid		2,000
Fair value of the contingent consideration		$ 3,000
Other intangibles				5,500
Goodwill				$ 4,394
Certain assets Of creative plan design limited | Other Intangible Assets
Acquisitions
Estimated useful life of other intangibles				12 years
Certain assets of six financial services companies
Acquisitions
Purchase price of acquisition						8,100
Purchase price in cash						6,700
Aggregate consideration in contingent consideration arrangements						1,400
Assets acquired						5,100
Other intangibles						4,900
Goodwill						$ 3,000
Certain assets of six financial services companies | Minimum
Acquisitions
Term of revenue target for contingent consideration arrangements						2 years
Certain assets of six financial services companies | Maximum
Acquisitions
Term of revenue target for contingent consideration arrangements						5 years
Axiom
Acquisitions
Purchase price of acquisition						$ 1,819
Purchase price in cash			$ 1,800
Other intangibles			1,200			1,176
Goodwill			$ 600			$ 625
Revenue				$ 600	100
Direct expenses				$ 700	$ 200
Acquisitions 2023 | Other Intangible Assets
Acquisitions
Estimated useful life of other intangibles				8 years
Subsequent events | New York Based Insurance Agency
Acquisitions
Purchase price in cash	4,200
Aggregate consideration in contingent consideration arrangements	$ 1,000