Restructuring and Other Charges - Summary of Restructuring by Major Type of Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Restructuring Charges [Line Items]
Restructuring costs	$ 9,454	$ 32,920	$ 92,061	$ 136,671
Lease Abandonments
Restructuring Charges [Line Items]
Restructuring costs	2,712	10,300	47,313	74,571
Involuntary Terminations
Restructuring Charges [Line Items]
Restructuring costs	4,120	20,359	32,606	58,648
Outside Services
Restructuring Charges [Line Items]
Restructuring costs	684	2,076	4,236	3,267
Other Restructuring Related
Restructuring Charges [Line Items]
Restructuring costs	$ 1,938	$ 185	$ 7,906	$ 185