Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 27, 2017	Aug. 28, 2016	Aug. 27, 2017	Aug. 28, 2016
Pension Benefits [Member]
Net periodic benefit cost:
Service cost	$ 2,510	$ 2,064	$ 7,452	$ 6,194
Interest cost	9,233	9,453	27,601	28,415
Expected return on plan assets	(12,162)	(12,105)	(36,399)	(36,401)
Amortization of prior service benefit	(16)	(15)	(46)	(46)
Amortization of actuarial loss	3,365	3,005	10,123	9,040
Curtailment loss (gain)	41	(361)	108	(361)
Net settlement loss	19	21	113	21
Net periodic benefit cost	2,990	2,062	8,952	6,862
Changes in accumulated other comprehensive loss:
Actuarial loss	(7)	0	(10)	170
Amortization of prior service benefit	16	15	46	46
Amortization of actuarial loss	(3,365)	(3,005)	(10,123)	(9,040)
Curtailment gain	0	396	0	396
Net settlement loss	(19)	(21)	(113)	(21)
Total recognized in accumulated other comprehensive loss	(3,375)	(2,615)	(10,200)	(8,449)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	(385)	(553)	(1,248)	(1,587)
Postretirement Benefits [Member]
Net periodic benefit cost:
Service cost	43	50	129	150
Interest cost	787	805	2,361	2,417
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	0	0	0	0
Amortization of actuarial loss	318	742	953	2,225
Curtailment loss (gain)	0	0	0	0
Net settlement loss	0	0	0	0
Net periodic benefit cost	1,148	1,597	3,443	4,792
Changes in accumulated other comprehensive loss:
Actuarial loss	0	0	0	0
Amortization of prior service benefit	0	0	0	0
Amortization of actuarial loss	(318)	(742)	(953)	(2,225)
Curtailment gain	0	0	0	0
Net settlement loss	0	0	0	0
Total recognized in accumulated other comprehensive loss	(318)	(742)	(953)	(2,225)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 830	$ 855	$ 2,490	$ 2,567