Pension Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 24, 2017	Jun. 30, 2018	Jun. 24, 2017
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 69	$ 96	$ 208	$ 288
Amortization of prior service credits	(124)	0	(374)	0
Amortization of net loss (gain)	(163)	(98)	(491)	(292)
Net periodic benefit cost	(218)	(2)	(657)	(4)
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	944	1,041	2,832	3,123
Expected return on plan assets	(473)	(537)	(1,420)	(1,611)
Amortization of net loss (gain)	920	1,301	2,762	3,901
Net periodic benefit cost	$ 1,391	$ 1,805	$ 4,174	$ 5,413