Employee Benefit Plans - amounts recognized in balance sheet (Details) (USD $)	Nov. 30, 2014	Nov. 24, 2013
Pension plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	$ 1,587,000	$ 1,331,000
Accrued benefit liability – current portion	(8,926,000)	(8,622,000)
Accrued benefit liability – long-term portion	(403,175,000)	(323,475,000)
Amount recognized in balance sheet	(410,514,000)	(330,766,000)
Accumulated other comprehensive loss:
Net actuarial loss	(394,090,000)	(343,148,000)
Net prior service benefit	548,000	666,000
Other comprehensive income (loss)	(393,542,000)	(342,482,000)
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	(11,871,000)	(13,347,000)
Accrued benefit liability – long-term portion	(122,213,000)	(122,248,000)
Amount recognized in balance sheet	(134,084,000)	(135,595,000)
Accumulated other comprehensive loss:
Net actuarial loss	(36,505,000)	(34,248,000)
Net prior service benefit	0	0
Other comprehensive income (loss)	$ (36,505,000)	$ (34,248,000)