Employee Benefit Plans - Schedule of Net Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 28, 2013
Components of net periodic benefit costs included in operating expenses [Abstract]
Settlement charge	$ (2,000)	$ 0	$ 0
Pension Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Interest cost	5,128	5,774	5,229
Expected return on plan assets	(4,913)	(5,102)	(5,281)
Settlement charge	2,000
Recognized net actuarial loss (gain)	4,522	4,492	5,285
Net periodic benefit costs	6,737	5,164	5,233
Retiree Health and Life Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Interest cost	575	645	594
Amortization of prior service credit	(490)	(490)	(490)
Recognized net actuarial loss (gain)	(196)	(181)
Net periodic benefit costs	$ (111)	$ (26)	$ 104