Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 1,744,014	$ 1,650,333	$ 1,645,319
Gross profit	319,275	329,186	346,473
Income before income taxes	77,435	100,548	110,888
Net income	$ 58,763	$ 74,861	$ 83,688
Earnings per share
Basic (usd per share)	$ 3.46	$ 4.43	$ 4.84
Diluted (usd per share)	$ 3.45	$ 4.42	$ 4.83