v3.26.1
Transactions with Affiliates - Schedule of Amounts Charged to UTSI (Detail) - Affiliates [Member] - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jul. 04, 2026
Jun. 28, 2025
Jul. 04, 2026
Jun. 28, 2025
Related Party Transaction [Line Items]        
Cost incurred for services provided by CenTra and affiliates $ 45,409 $ 30,856 $ 85,100 $ 61,363
Insurance [Member]        
Related Party Transaction [Line Items]        
Cost incurred for services provided by CenTra and affiliates 32,852 21,579 60,232 44,646
Real estate rent and related costs [Member]        
Related Party Transaction [Line Items]        
Cost incurred for services provided by CenTra and affiliates 8,326 5,065 16,713 8,951
Administrative support services [Member]        
Related Party Transaction [Line Items]        
Cost incurred for services provided by CenTra and affiliates 2,138 1,728 4,607 3,729
Truck fuel, maintenance and other operating costs [Member]        
Related Party Transaction [Line Items]        
Cost incurred for services provided by CenTra and affiliates $ 2,093 $ 2,484 $ 3,548 $ 4,037