v3.25.4
Accounting Policies (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Oct. 01, 2019
Sep. 30, 2019
Revenue from Contract with Customer [Abstract]            
Unbilled $ 810,000 $ 810,000        
Disaggregation of Revenue [Line Items]            
Revenues 6,812,000 6,581,000 $ 6,486,000      
Revenue Composition [Abstract]            
Gross billings 45,565,000 43,752,000 43,141,000      
Worksite employee payroll cost 38,753,000 37,171,000 36,655,000      
Revenues $ 6,812,000 6,581,000 6,486,000      
Health Insurance Costs [Abstract]            
Percentage of our health insurance coverage provided by United 85.00%          
Number of days in advance of the beginning of a reporting quarter United establishes cash funding rates 90 days          
Required accumulated cash surplus $ 9,000          
Required deposit equal to approximately one day of claims funding activity 7,000          
Amount which plan costs were less than the net premiums paid and owed (18,000)          
Premiums owed to United (7,000)          
Benefits costs incurred (reduced) related to run-off 11,000 (29,000)        
Workers' Compensation Costs [Abstract]            
Company's maximum economic burden for the first layer of claims per occurrence         $ 1,500 $ 1,000
Company's maximum aggregate economic burden for claims in excess of 1 million per policy year         $ 6,000 $ 6,000
Decrease Increase in accrued workers' compensation costs for changes in estimated losses $ (29,000) $ (32,000)        
U.S. Treasury rates that correspond with the weighted average estimated claim payout period (in hundredths) 3.90% 4.30%        
Incurred but not paid workers compensation liabilities [Abstract]            
Liability for Unpaid Claims and Claims Adjustment Expense, Adjustments   $ 204,000 220,000      
Workers' Compensation Expense $ 74,000 65,000        
Workers' Compensation Discount, Changed during period (12,000) (12,000)        
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid (82,000) (69,000)        
Workers' Compensation Liability 184,000 204,000        
WorkersCompensationLiabilityNetOfAdminFeesCurrent 82,000 69,000        
Workers' Compensation Liability, Noncurrent 102,000 135,000        
Workers' Compensation Liability 184,000 204,000        
Workers compensation administrative fees accrued 2,000          
Undiscounted accrued workers' compensation costs $ 227,000 240,000        
Time period incurred claims expected to be paid recorded as restricted cash 1 year          
Time period incurred claims expected to be paid included in deposits Greater than 1 year          
Restricted cash $ 82,000 69,000 57,000 $ 50,000    
Deposits workers compensation 148,000 178,000 198,000 $ 196,000    
WorkersCompDepositsHeldInTrust $ 230,000          
Time period estimate of incurred claim costs to be paid included in short-term liabilities 1 year          
Time period estimate of incurred claim costs to be paid included in long term liabilities beyond one year          
ReturnOfExcessClaimFunds $ 29,000          
Northeast [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 1,873,000 1,801,000 1,757,000      
Revenue Composition [Abstract]            
Revenues 1,873,000 1,801,000 1,757,000      
Southeast [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 972,000 926,000 907,000      
Revenue Composition [Abstract]            
Revenues 972,000 926,000 907,000      
Central [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 1,230,000 1,195,000 1,170,000      
Revenue Composition [Abstract]            
Revenues 1,230,000 1,195,000 1,170,000      
Southwest [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 1,279,000 1,245,000 1,250,000      
Revenue Composition [Abstract]            
Revenues 1,279,000 1,245,000 1,250,000      
West [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 1,388,000 1,344,000 1,337,000      
Revenue Composition [Abstract]            
Revenues 1,388,000 1,344,000 1,337,000      
Other Revenues [Member]            
Disaggregation of Revenue [Line Items]            
Revenues 70,000 70,000 65,000      
Revenue Composition [Abstract]            
Revenues $ 70,000 $ 70,000 $ 65,000