Accrued Payroll and Benefit Costs - Accrued Payroll/Benefit Costs and Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Payroll and benefits	$ 414,580	$ 449,246
Payroll taxes	67,458	74,117
Workers’ compensation	17,772	16,820
Accrued payroll and benefit costs	499,810	540,183
Other Liabilities
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Applicable payroll taxes deferred	$ 51,100	$ 51,100