Pension Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,282	$ 1,443	$ 3,846	$ 4,330
Expected return on plan assets	(1,228)	(1,275)	(3,685)	(3,826)
Amortization of net loss (gain)	1,131	1,123	3,392	3,369
Net periodic benefit cost	1,185	1,291	3,553	3,873
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	144	161	431	484
Amortization of prior service costs	(122)	(122)	(367)	(367)
Amortization of net loss (gain)	(49)	(46)	(147)	(137)
Net periodic benefit cost	$ (27)	$ (7)	$ (83)	$ (20)