Note 10 - Stock-based Compensation (Details Textual) - USD ($)	12 Months Ended
	May 01, 2021	May 02, 2020	Apr. 27, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	266,500	0	18,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)	7 years 2 months 12 days		8 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	19.36%		21.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	3.85%		2.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	1.30%		1.60%
Share-based Payment Arrangement, Expense	$ 462,000	$ 126,000	$ 251,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	1,900,000	4,900,000	2,200,000
Proceeds from Stock Options Exercised	491,000	740,000	456,000
Share-based Payment Arrangement, Expense, Tax Benefit	382,000	$ 974,000	$ 443,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)		$ 13.01
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 490,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	4 years 1 month 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)	4 years 10 months 24 days	3 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 16,900,000	$ 7,000,000.0
Omnibus Plan [Member]
Share Based Compensation Arrangement by Share Based Payment Award Number of Shares Authorized Per Individual (in shares)	1,680,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	10 years
Omnibus Plan [Member] | Stock Options or Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	9,600,000
Omnibus Plan [Member] | SARS Dividend Equivalents and Other Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	9,600,000
Special Stock Option Plan [Member] | Determined by Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	3,600,000
Special Stock Option Plan [Member] | Determined By Chairman Member
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	100,000
KEEP Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	480,000
Share Based Compensation Arrangement by Share Based Payment Award Number of Shares Authorized Per Individual (in shares)	12,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	6 years
Share Based Compensation Arrangement by Share Based Payment Award Percentage of Purchased Shares Matched	50.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants, Period (Year)	2 years
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	60.00%