Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Income) and Contributions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 27, 2016	Aug. 29, 2015	Aug. 27, 2016	Aug. 29, 2015
Amortization of unrecognized:
Cash contributions	$ 100		$ 201
Pension Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	370	$ 361	1,112	$ 1,430
Interest cost	1,554	2,020	4,673	5,767
Expected return on plan assets	(2,579)	(2,843)	(7,757)	(8,686)
Curtailment	0	(1)	0	(1)
Amortization of unrecognized:
Prior service cost	0	(2)	0	(4)
Net actuarial loss (gain)	953	826	2,865	2,760
Net periodic benefit cost	298	363	893	1,268
Cash contributions	89	101	168	354
Postretirement Healthcare Benefit Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	2	2	6	6
Amortization of unrecognized:
Prior service cost	(31)	(31)	(93)	(93)
Net actuarial loss (gain)	(23)	(37)	(69)	(111)
Net periodic benefit cost	(52)	(66)	(156)	(198)
Cash contributions	$ 11	$ 15	$ 33	$ 45