Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Apr. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (shares)	37,111,667
Beginning Balance	$ 2,240,838	$ 1,932,679	$ 1,643,205
Net income	446,691	339,790	312,900
Dividends declared	(57,488)	(52,092)	(49,091)
Exercise of stock options		133	1,784
Stock-based compensation (net of tax withholding on employee share-based awards)	$ 30,625	$ 20,328	23,881
Ending Balance (shares)	37,263,248	37,111,667
Ending Balance	$ 2,660,666	$ 2,240,838	$ 1,932,679
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (shares)	37,111,667	36,949,878	36,806,325
Beginning Balance	$ 79,412	$ 58,951	$ 33,286
Exercise of stock options (shares)		3,000	40,189
Exercise of stock options		$ 133	$ 1,784
Stock-based compensation (shares)	151,581	158,789	103,364
Stock-based compensation (net of tax withholding on employee share-based awards)	$ 30,625	$ 20,328	$ 23,881
Ending Balance (shares)	37,263,248	37,111,667	36,949,878
Ending Balance	$ 110,037	$ 79,412	$ 58,951
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	2,161,426	1,873,728	1,609,919
Net income		339,790	312,900
Dividends declared	(57,488)	(52,092)	(49,091)
Ending Balance	$ 2,550,629	$ 2,161,426	$ 1,873,728