Note 11 (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Sep. 28, 2019
Debt Securities, Held-to-maturity, Total	$ 110,428,000		$ 110,428,000		$ 130,451,000
Proceeds from Sale and Maturity of Marketable Securities, Total	12,156,000	$ 6,012,000	30,938,000	$ 23,137,000
Marketable Securities, Gain (Loss), Total	(2,059,000)	(973,000)	(2,070,000)	(284,000)
Marketable Securities, Unrealized Gain (Loss), Total	(1,993,000)	$ (2,064,000)	(267,000)	$ 760,000
Corporate Bond Securities [Member]
Debt Securities, Held-to-maturity, Total	$ 99,000,000		$ 99,000,000
Investment Securities Maturity Term (Year)			2 years