Note 11 (Details Textual)	3 Months Ended		6 Months Ended
	Mar. 25, 2017 USD ($)	Mar. 26, 2016 USD ($)	Mar. 25, 2017 USD ($)	Mar. 26, 2016 USD ($)	Sep. 24, 2016 USD ($)
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 336,000		$ 336,000		$ 602,000
Held-to-maturity Securities	122,288,000		122,288,000		104,271,000
Proceeds from Sale and Maturity of Marketable Securities	4,629,000	$ 4,186,000	5,104,000	$ 5,384,000
Marketable Securities, Gain (Loss)		$ (297,000)		$ (406,000)
Four Mutual Funds [Member]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	269,000		$ 269,000
Number of Funds			4
Marketable Securities	12,700,000		$ 12,700,000
Preferred Stock [Member]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	67,000		$ 67,000		$ 82,000
Classification Of Noncurrent Asset, Mutual Funds, Period			1 year
Corporate Bond Securities [Member]
Held-to-maturity Securities	$ 108,000,000		$ 108,000,000
Investment Securities Maturity Term			3 years