Employee Benefit Plans - Defined benefit plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 29, 2020	Nov. 24, 2019	Nov. 25, 2018
Pension plans, defined benefit [Member]
Net periodic benefit cost:
Service cost	$ 4,026	$ 3,377	$ 3,602
Interest cost	30,643	41,341	36,070
Expected return on plan assets	(41,189)	(42,098)	(48,830)
Amortization of prior service benefit	(62)	(61)	(65)
Amortization of actuarial loss	13,407	13,306	12,650
Curtailment loss	(650)	13	38
Net settlement (gain) loss	14,699	(56)	(102)
Net periodic benefit cost	20,874	15,822	3,363
Changes in accumulated other comprehensive loss:
Actuarial loss (gain)	(34,821)	6,309	15,373
Amortization of prior service benefit (cost)	62	61	65
Amortization of actuarial loss	(13,407)	(13,306)	(12,650)
Net settlement gain (loss)	(14,699)	56	102
Total recognized in accumulated other comprehensive loss	(62,123)	(6,880)	2,890
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	(41,249)	8,942	6,253
Other postretirement benefit plans, defined benefit [Member]
Net periodic benefit cost:
Service cost	48	65	113
Interest cost	1,665	3,042	2,718
Expected return on plan assets	0	0	0
Amortization of prior service benefit	0	0	0
Amortization of actuarial loss	324	465	872
Curtailment loss	0	0	0
Net settlement (gain) loss	0	0	0
Net periodic benefit cost	2,037	3,572	3,703
Changes in accumulated other comprehensive loss:
Actuarial loss (gain)	1,531	(2,903)	(6,354)
Amortization of prior service benefit (cost)	0	0	0
Amortization of actuarial loss	(324)	(465)	(872)
Net settlement gain (loss)	0	0	0
Total recognized in accumulated other comprehensive loss	1,207	(3,368)	(7,226)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 3,244	$ 204	$ (3,523)