Employee Benefit Plans - Amounts recognized in balance sheet (Details) - USD ($)	Nov. 28, 2021	Nov. 29, 2020
Pension plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	$ 98,278,000	$ 62,161,000
Accrued benefit liability – current portion(2)	(9,770,000)	(9,663,000)
Accrued benefit liability – long-term portion(2)	(151,398,000)	(163,836,000)
Amount recognized in balance sheet	(62,890,000)	(111,338,000)
Accumulated other comprehensive loss:
Net actuarial loss	(264,729,000)	(296,330,000)
Net prior service benefit	182,000	259,000
Other comprehensive income (loss)	(264,547,000)	(296,071,000)
Other postretirement benefit plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	0	0
Accrued benefit liability – current portion(2)	(6,398,000)	(7,112,000)
Accrued benefit liability – long-term portion(2)	(51,439,000)	(60,249,000)
Amount recognized in balance sheet	(57,837,000)	(67,361,000)
Accumulated other comprehensive loss:
Net actuarial loss	(8,956,000)	(12,491,000)
Net prior service benefit	0	0
Other comprehensive income (loss)	$ (8,956,000)	$ (12,491,000)