Reportable Segments - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Jan. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Oct. 02, 2016
Reportable Segments
Revenue	$ 739,343	$ 764,795	$ 700,262	$ 759,749	$ 735,188	$ 685,539	$ 663,781	$ 668,851	$ 2,964,148	$ 2,753,360	$ 2,583,469
United States
Reportable Segments
Revenue									2,232,013	2,018,841	1,858,551
Long-Lived Assets	59,164				58,965				59,164	58,965	59,334
Foreign countries
Reportable Segments
Revenue									732,135	734,519	724,918
Long-Lived Assets	$ 34,934				$ 34,183				$ 34,934	$ 34,183	$ 39,067