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Retirement Plans - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost recognized $ 28,217,000 $ 27,599,000 $ 25,595,000
Defined benefit plan, voluntary contribution $ 3,265,000 1,506,000  
Corridor amount 10.00%    
Net unrecognized actuarial losses expected to be recognized in 2023 $ 12,627,000    
Net unrecognized actuarial losses expected to be recognized in 2023, net of tax 10,065,000,000    
Net periodic benefit cost (income), non-service cost $ 8,767,000 (1,499,000) (3,472,000)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Other Nonoperating Income (Expense)    
U.K Plan      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate used to compute periodic benefit cost 5.80%    
Expected long-term rates of return on plans' assets in next fiscal year 6.20%    
U.S.      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, voluntary contribution $ 0 0 $ 9,000,000
Increase (decrease) in projected benefit obligation   $ (1,393,852)  
Discount rate used to compute periodic benefit cost 4.87%    
Expected long-term rates of return on plans' assets in next fiscal year 5.90%