Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 30, 2015	Aug. 24, 2014	Aug. 30, 2015	Aug. 24, 2014
Changes in accumulated other comprehensive loss:
Total recognized in accumulated other comprehensive loss	$ (3,083)	$ (2,339)	$ (9,912)	$ (6,857)
Pension Benefits [Member]
Net periodic benefit cost (income):
Service cost	2,092	2,106	6,310	6,431
Interest cost	11,796	13,775	35,426	41,312
Expected return on plan assets	(12,715)	(13,909)	(38,148)	(41,788)
Amortization of prior service benefit	(15)	0	(46)	(36)
Amortization of actuarial loss	3,149	2,692	9,472	8,097
Curtailment loss	(118)	(1,790)	269	2,653
Net settlement gain	(45)	0	(45)	(73)
Net periodic benefit cost	4,144	2,874	13,238	16,596
Changes in accumulated other comprehensive loss:
Actuarial gain (loss)	(579)	0	(579)	0
Amortization of prior service benefit	15	0	46	36
Amortization of actuarial loss	(3,149)	(2,692)	(9,472)	(8,097)
Curtailment (loss) gain	118	(1)	(269)	114
Net settlement gain	45	0	45	4
Total recognized in accumulated other comprehensive loss	(3,550)	(2,693)	(10,229)	(7,943)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	594	181	3,009	8,653
Postretirement Benefits [Member]
Net periodic benefit cost (income):
Service cost	63	63	188	192
Interest cost	1,147	1,292	3,441	3,907
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	0	(1)	0	(4)
Amortization of actuarial loss	1,127	1,063	3,383	3,139
Curtailment loss	0	0	0	733
Net settlement gain	0	0	0	0
Net periodic benefit cost	2,337	2,417	7,012	7,967
Changes in accumulated other comprehensive loss:
Actuarial gain (loss)	0	0	0	0
Amortization of prior service benefit	0	1	0	4
Amortization of actuarial loss	(1,127)	(1,063)	(3,383)	(3,139)
Curtailment (loss) gain	0	0	0	0
Net settlement gain	0	0	0	0
Total recognized in accumulated other comprehensive loss	(1,127)	(1,062)	(3,383)	(3,135)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 1,210	$ 1,355	$ 3,629	$ 4,832