Employee Stock Purchase and Stock Incentive Plans (Stock Issuance Activity Under the 1989 ESPP and the GESPP) (Details) - USD ($)		12 Months Ended
	Jan. 19, 2017	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount (percent) available to employees on the purchase of common stock		5.00%
Aggregate Purchase Price Paid for Shares Sold:		$ 27,812,601	$ 27,295,425	$ 23,831,467
Aggregate Number of Shares Sold:		333,078	389,423	394,304
Number of remaining shares reserved for issuance at September 27, 2019 (in shares)		5,632,447
Under the 1989 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Purchase Price Paid for Shares Sold:		$ 25,364,252	$ 24,824,232	$ 21,590,858
Aggregate Number of Shares Sold:		304,018	354,580	357,899
Increase in number of shares authorized	4,350,000
Number of remaining shares reserved for issuance at September 27, 2019 (in shares)		3,529,357
Under the GESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Purchase Price Paid for Shares Sold:		$ 2,448,349	$ 2,471,193	$ 2,240,609
Aggregate Number of Shares Sold:		29,060	34,843	36,405
Increase in number of shares authorized	150,000
Number of remaining shares reserved for issuance at September 27, 2019 (in shares)		74,672