Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 24, 2014	Aug. 25, 2013	Aug. 24, 2014	Aug. 25, 2013
Net periodic benefit cost (income):
Curtailment loss (gain)			$ 0	$ (815)
Changes in accumulated other comprehensive loss:
Total recognized in accumulated other comprehensive loss	(2,339)	(3,718)	(6,857)	(10,826)
Pension Benefits [Member]
Net periodic benefit cost (income):
Service cost	2,106	2,052	6,431	6,548
Interest cost	13,775	12,918	41,312	38,978
Expected return on plan assets	(13,909)	(14,105)	(41,788)	(42,065)
Amortization of prior service benefit	0	(24)	(36)	(61)
Amortization of actuarial loss	2,692	3,810	8,097	12,241
Curtailment loss (gain)	(1,790)	(305)	2,653	(815)
Net settlement (gain) loss	0	415	(73)	1,044
Net periodic benefit cost	2,874	4,761	16,596	15,870
Changes in accumulated other comprehensive loss:
Amortization of prior service benefit	0	24	36	61
Amortization of actuarial loss	(2,692)	(3,810)	(8,097)	(12,241)
Curtailment gain (loss)	(1)	(12)	114	497
Net settlement gain (loss)	0	(406)	4	(590)
Total recognized in accumulated other comprehensive loss	(2,693)	(4,204)	(7,943)	(12,273)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	181	557	8,653	3,597
Postretirement Benefits [Member]
Net periodic benefit cost (income):
Service cost	63	94	192	282
Interest cost	1,292	1,239	3,907	3,718
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	(1)	(122)	(4)	(366)
Amortization of actuarial loss	1,063	1,691	3,139	5,074
Curtailment loss (gain)	0	0	733	0
Net settlement (gain) loss	0	0	0	0
Net periodic benefit cost	2,417	2,902	7,967	8,708
Changes in accumulated other comprehensive loss:
Amortization of prior service benefit	1	122	4	366
Amortization of actuarial loss	(1,063)	(1,691)	(3,139)	(5,074)
Curtailment gain (loss)	0	0	0	0
Net settlement gain (loss)	0	0	0	0
Total recognized in accumulated other comprehensive loss	(1,062)	(1,569)	(3,135)	(4,708)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 1,355	$ 1,333	$ 4,832	$ 4,000