Note 10 - Stock-based Compensation (Details Textual) - USD ($)		12 Months Ended
		Apr. 30, 2022	May 01, 2021	May 02, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		30,000	266,500	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term (Year)		6 years 6 months	7 years 2 months 12 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate		20.74%	19.36%
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate		1.22%	3.85%
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate		2.48%	1.30%
Share-Based Payment Arrangement, Expense		$ 695,000	$ 462,000	$ 126,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value		1,400,000	1,900,000	4,900,000
Proceeds from Stock Options Exercised		335,000	491,000	740,000
Share-Based Payment Arrangement, Expense, Tax Benefit		$ 283,000	$ 382,000	$ 974,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)	[1]	$ 44.73
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total		$ 3,000,000.0
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		6 years 2 months 12 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)		4 years 2 months 12 days	4 years 10 months 24 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value		$ 10,800,000	$ 16,900,000
Omnibus Plan [Member]
Share Based Compensation Arrangement by Share Based Payment Award Number of Shares Authorized Per Individual (in shares)		3,360,000
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%

[1] Weighted average exercise price.