Employee Benefit Plans - Defined benefit plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 26, 2017	Nov. 27, 2016	Nov. 29, 2015
Pension plans, defined benefit [Member]
Net periodic benefit cost:
Service cost	$ 9,975	$ 8,234	$ 8,352
Interest cost	36,853	37,819	47,179
Expected return on plan assets	(48,581)	(48,422)	(50,825)
Amortization of prior service benefit	(62)	(61)	(61)
Amortization of actuarial loss	13,489	12,036	12,578
Curtailment (gain) loss	106	(140)	656
Special termination benefit	0	0	0
Net settlement loss (gain)	126	49	(45)
Net periodic benefit cost	11,906	9,515	17,834
Changes in accumulated other comprehensive loss:
Actuarial loss (gain)	(9,785)	32,187	(15,228)
Amortization of prior service benefit (cost)	62	61	61
Amortization of actuarial loss	(13,489)	(12,036)	(12,578)
Curtailment gain (loss)	0	173	(656)
Net settlement (loss) gain	(126)	(49)	45
Total recognized in accumulated other comprehensive loss	(23,338)	20,336	(28,356)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	(11,432)	29,851	(10,522)
Other postretirement benefit plans, defined benefit [Member]
Net periodic benefit cost:
Service cost	172	200	251
Interest cost	3,148	3,223	4,588
Expected return on plan assets		0	0
Amortization of prior service benefit	0	0	0
Amortization of actuarial loss	1,271	2,967	4,511
Curtailment (gain) loss	0	0	0
Special termination benefit		0	0
Net settlement loss (gain)		0	0
Net periodic benefit cost	4,591	6,390	9,350
Changes in accumulated other comprehensive loss:
Actuarial loss (gain)	(5,516)	5,556	(5,918)
Amortization of prior service benefit (cost)	0	0	0
Amortization of actuarial loss	(1,271)	(2,967)	(4,511)
Curtailment gain (loss)	0	0	0
Net settlement (loss) gain	0	0	0
Total recognized in accumulated other comprehensive loss	(6,787)	2,589	(10,429)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ (2,196)	$ 8,979	$ (1,079)