Postretirement and Postemployment Benefits - Fair Value Hierarchy of Benefit Plan Assets (Details) - USD ($) $ in Thousands	Sep. 24, 2023	Sep. 25, 2022	Sep. 26, 2021
NAV | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets		$ 2,782
Level 1 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets		0
Level 2 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets		0
Level 3 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets		0
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	$ 25,809	23,903	$ 26,802
Other Postretirement Benefits Plan | NAV | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | NAV | Domestic equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	870	791
Other Postretirement Benefits Plan | NAV | Emerging equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | NAV | International equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | NAV | Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | NAV | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	2,979
Other Postretirement Benefits Plan | Level 1 | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	93	26
Other Postretirement Benefits Plan | Level 1 | Domestic equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	2,303	1,910
Other Postretirement Benefits Plan | Level 1 | Emerging equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	535	456
Other Postretirement Benefits Plan | Level 1 | International equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	814	573
Other Postretirement Benefits Plan | Level 1 | Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	17,615	17,248
Other Postretirement Benefits Plan | Level 1 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0
Other Postretirement Benefits Plan | Level 2 | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 2 | Domestic equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 2 | Emerging equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 2 | International equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	600	480
Other Postretirement Benefits Plan | Level 2 | Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 2 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0
Other Postretirement Benefits Plan | Level 3 | Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 3 | Domestic equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 3 | Emerging equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 3 | International equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	0
Other Postretirement Benefits Plan | Level 3 | Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	0	$ 0
Other Postretirement Benefits Plan | Level 3 | Hedge fund investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Postretirement assets	$ 0