Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands		Total	Class A Common Shares	Class B Common Shares	Common stock Class A Common Shares		Common stock Class B Common Shares	Additional paid-in capital	Retained earnings/deficit	Treasury stock
Beginning Balance (in shares) at Apr. 30, 2020					35,000,649		1,821,587
Beginning Balance at Apr. 30, 2020		$ 119,422			$ 3,500		$ 182	$ 150,312	$ (9,013)	$ (25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		628,917			628,917
Proceeds from stock options exercised		$ 6,697			$ 63			6,634
Stock-based compensation		2,546						2,546
Net earnings		8,089							8,089
Dividends declared ($0.44 per share)		(14,363)							(14,363)
Ending Balance (in shares) at Apr. 30, 2021					35,629,566		1,821,587
Ending Balance at Apr. 30, 2021		$ 122,391			$ 3,563		$ 182	159,492	(15,287)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		776,129			776,129
Proceeds from stock options exercised		$ 8,578			$ 78			8,500
Stock-based compensation		3,956						3,956
Net earnings		12,782							12,782
Dividends declared ($0.44 per share)	[1]	(14,731)							(14,731)
Ending Balance (in shares) at Apr. 30, 2022			36,405,695	1,821,587	36,405,695		1,821,587
Ending Balance at Apr. 30, 2022		$ 132,976			$ 3,641		$ 182	171,948	(17,236)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		501,547			501,547	[1]
Proceeds from stock options exercised	[1]	$ 5,641			$ 50			5,591
Stock-based compensation		5,183						5,183
Net earnings		10,421							10,421
Dividends declared ($0.44 per share)	[1]	(14,887)							(14,887)
Ending Balance (in shares) at Apr. 30, 2023			36,907,242	1,821,587	36,907,242		1,821,587
Ending Balance at Apr. 30, 2023		$ 139,334			$ 3,691		$ 182	$ 182,722	$ (21,702)	$ (25,559)

[1] *Amounts adjusted for rounding