Employee Benefit Plans - amounts recognized in balance sheet (Details) - USD ($) $ in Thousands	Nov. 29, 2015	Nov. 30, 2014
Pension plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	$ 8,842	$ 1,587
Accrued benefit liability – current portion	(9,044)	(8,926)
Accrued benefit liability – long-term portion	(355,612)	(403,175)
Amount recognized in balance sheet	(355,814)	(410,514)
Accumulated other comprehensive loss:
Net actuarial loss	(365,657)	(394,090)
Net prior service benefit	471	548
Other comprehensive income (loss)	(365,186)	(393,542)
Other postretirement benefit plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	0	0
Accrued benefit liability – current portion	(12,500)	(11,871)
Accrued benefit liability – long-term portion	(105,240)	(122,213)
Amount recognized in balance sheet	(117,740)	(134,084)
Accumulated other comprehensive loss:
Net actuarial loss	(26,076)	(36,505)
Net prior service benefit	0	0
Other comprehensive income (loss)	$ (26,076)	$ (36,505)