Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 28, 2016	Aug. 30, 2015	Aug. 28, 2016		Aug. 30, 2015
Net periodic benefit cost (income):
Curtailment (gain) loss, net			$ 35		$ 0
Pension Benefits [Member]
Net periodic benefit cost (income):
Service cost	$ 2,064	$ 2,092	6,194		6,310
Interest cost	9,453	11,796	28,415	[1]	35,426	[1]
Expected return on plan assets	(12,105)	(12,715)	(36,401)		(38,148)
Amortization of prior service benefit	(15)	(15)	(46)		(46)
Amortization of actuarial loss	3,005	3,149	9,040		9,472
Curtailment (gain) loss, net	(361)	(118)	(361)		269
Other Comprehensive Loss Income Reclassification Of Defined Benefit Plans, Net Settlement Loss, Net Of Tax	21	(45)	21		(45)
Net periodic benefit cost	2,062	4,144	6,862		13,238
Changes in accumulated other comprehensive loss:
Actuarial gain (loss)	0	(579)	170		(579)
Amortization of prior service benefit	15	15	46		46
Amortization of actuarial loss	(3,005)	(3,149)	(9,040)		(9,472)
Curtailment gain (loss)	396	118	396		(269)
Total recognized in accumulated other comprehensive loss	(2,615)	(3,550)	(8,449)		(10,229)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	(553)	594	(1,587)		3,009
Postretirement Benefits [Member]
Net periodic benefit cost (income):
Service cost	50	63	150		188
Interest cost	805	1,147	2,417	[1]	3,441	[1]
Expected return on plan assets	0	0	0		0
Amortization of prior service benefit	0	0	0		0
Amortization of actuarial loss	742	1,127	2,225		3,383
Curtailment (gain) loss, net	0	0	0		0
Other Comprehensive Loss Income Reclassification Of Defined Benefit Plans, Net Settlement Loss, Net Of Tax	0	0	0		0
Net periodic benefit cost	1,597	2,337	4,792		7,012
Changes in accumulated other comprehensive loss:
Actuarial gain (loss)	0	0	0		0
Amortization of prior service benefit	0	0	0		0
Amortization of actuarial loss	(742)	(1,127)	(2,225)		(3,383)
Curtailment gain (loss)	0	0	0		0
Total recognized in accumulated other comprehensive loss	(742)	(1,127)	(2,225)		(3,383)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 855	$ 1,210	$ 2,567		$ 3,629

[1] The decrease in interest cost is primarily due to the election made at the end of 2015 to adopt the spot-rate approach to determine the interest cost component of pension and postretirement expense.