Note 13 - Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	May 02, 2020	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	May 02, 2020	Apr. 27, 2019	Apr. 28, 2018
Net sales	$ 262,401	$ 222,814	$ 251,611	$ 263,568	$ 239,914	$ 220,892	$ 260,709	$ 292,590	$ 1,000,394	$ 1,014,105	$ 975,734
Gross profit	98,657	82,095	92,814	96,574	84,578	80,554	103,524	115,694	370,140	384,350	391,135
Net income	$ 36,213	$ 26,563	$ 32,654	$ 34,542	$ 26,135	$ 24,811	$ 41,077	$ 48,830	$ 129,972	$ 140,853	$ 149,774
Earnings per common share – basic (in dollars per share)	$ 78	$ 57	$ 70	$ 74	$ 56	$ 53	$ 88	$ 1.05	$ 2.79	$ 3.02	$ 3.21
Earnings per common share – diluted (in dollars per share)	$ 77	$ 57	$ 70	$ 74	$ 56	$ 53	$ 88	$ 1.04	$ 2.78	$ 3.00	$ 3.19