Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	$ 157,709	$ 143,499
Available-for-sale debt securities	38,509	39,459	$ 43,485
Deferred compensation plan liabilities	(157,709)	(143,499)
Bank debt	(437,800)	(312,400)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets	157,709	143,499
Available-for-sale debt securities	38,509	39,459
Other depository assets	2,064	1,031
Deferred compensation plan liabilities	(157,709)	(143,499)
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	5,281	3,999
Bank debt	(436,344)	(310,826)
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent purchase price liabilities	$ (94,186)	$ (114,946)