v3.26.1
Segment Information and Geographical Data (Narrative) (Details)
$ in Thousands
3 Months Ended
Mar. 27, 2026
USD ($)
Segment
Dec. 26, 2025
USD ($)
May 15, 2025
USD ($)
Segment Reporting Information [Line Items]      
Number of operating segments | Segment 3    
Number of reportable segments | Segment 3    
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] Chief Executive Officer [Member]    
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description The CODM primarily uses revenue before reimbursement generated by the segment, cost of sales, gross margin, selling, general and administrative costs and contribution margin as a measure of profitability for each of its segments as these measures provide a comprehensive view of the segments’ financial performance. The measurement criteria for segment contribution is substantially the same for each reportable segment, excluding any unusual or infrequent items, if any.    
Goodwill $ 90,187 $ 90,659  
Goodwill included in foreign assets 14,900 15,100  
Global S&BT [Member]      
Segment Reporting Information [Line Items]      
Goodwill 63,495 63,967  
United Kingdom [Member]      
Segment Reporting Information [Line Items]      
Goodwill 13,900 $ 14,100  
Spend Matters LLC [Member]      
Segment Reporting Information [Line Items]      
Intangible assets     $ 2,000
Spend Matters LLC [Member] | United States [Member]      
Segment Reporting Information [Line Items]      
Intangible assets $ 4,000