v3.25.1
Pension, Postretirement and Postemployment Defined Benefit Plans - Net Periodic Cost (Benefit) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 30, 2025
Mar. 24, 2024
Mar. 30, 2025
Mar. 24, 2024
Pension Plan        
Defined Benefit Plan Disclosure [Line Items]        
Service cost for benefits earned during the period $ 1 $ 1 $ 2 $ 2
Interest cost on projected benefit obligation 2,034 2,253 4,068 4,768
Expected return on plan assets (2,319) (2,310) (4,637) (4,763)
Amortization of net (gain) loss 0 (1) 0 (3)
Amortization of prior service benefit 212 212 424 424
Settlement gain 0 0 0 (2,409)
Pension and postretirement medical benefit (72) 155 (143) (1,981)
Postretirement Medical Plans        
Defined Benefit Plan Disclosure [Line Items]        
Service cost for benefits earned during the period 1 13 2 25
Interest cost on projected benefit obligation 108 149 217 298
Expected return on plan assets (410) (320) (821) (639)
Amortization of net (gain) loss (292) (308) (584) (617)
Amortization of prior service benefit (71) (94) (142) (188)
Curtailment gain 0 0 0 (1,184)
Pension and postretirement medical benefit $ (664) $ (560) $ (1,328) $ (2,305)