Restructuring Charges (Narrative) (Details) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended	17 Months Ended
	Apr. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)	Apr. 02, 2016 USD ($)	Apr. 01, 2017 USD ($) employee	Apr. 02, 2016 USD ($)	Sep. 30, 2016 USD ($)	Apr. 01, 2017 USD ($)	Sep. 30, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Charge to operations, net	$ 464		$ 4,579	$ 6,749	$ 41,726		$ 83,700
Restructuring Reserve	13,149		15,474	13,149	15,474	$ 36,608	13,149	$ 15,254
Employee severance and related benefits [Member]
Restructuring Cost and Reserve [Line Items]
Charge to operations, net				2,861	41,362
Severance Costs	100					600
Restructuring Reserve	8,976		14,517	8,976	14,517	35,177	8,976	14,086
Facility closures and related costs [Member]
Restructuring Cost and Reserve [Line Items]
Charge to operations, net				3,888	364
Restructuring Reserve	4,173		$ 957	$ 4,173	$ 957	$ 1,431	4,173	$ 1,168
Restructuring Plan 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | employee				795
Q116 plan [Domain] | Employee severance and related benefits [Member]
Restructuring Cost and Reserve [Line Items]
Charge to operations, net	400	$ 6,300
Future Charges [Member] | Facility closures and related costs [Member]
Restructuring Cost and Reserve [Line Items]
Charge to operations, net				$ 3,000
Accrued Expenses and Other Current Liabilities [Member] | Facility closures and related costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	2,200			2,200			2,200
Other Noncurrent Liabilities [Member] | Facility closures and related costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	2,000			2,000			2,000
Restructuring Charges [Member] | Facility closures and related costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 2,200			$ 2,200			$ 2,200