Note K - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 24, 2022	Sep. 25, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)	10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)	462,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Discount from Market Price, Offering Date	85.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value	$ 2.1	$ 4.1	$ 6.0
Proceeds from Stock Options Exercised	13.1	14.1	18.7
Share-Based Payment Arrangement, Exercise of Option, Tax Benefit	0.1	$ 0.7	$ 1.2
Incentive Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)		$ 23.36	$ 31.2
Non-qualified Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)		$ 23.36	$ 29.76
Share-Based Payment Arrangement, Option [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 2.1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	3 years
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 2.5
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)	3,165	(0)	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	21,864	9,200	0
Performance Shares [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 2.4
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	21,260	8,868
Employee Stock Purchase Plan [Member]
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)	17,231	16,274	11,988
Share Price (in dollars per share)	$ 121.53	$ 124.94	$ 116.03
Share-Based Payment Arrangement, Expense	$ 0.6	$ 0.3	$ 0.6

J&J SNACK FOODS CORP 10-K