Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - 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 deficit	Treasury stock
Beginning balance (in shares) at Apr. 30, 2022					36,405,695		1,821,587
Beginning 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)		43,000			43,000
Proceeds from stock options exercised		$ 471			$ 4			467
Stock-based compensation		1,306						1,306
Net earnings		2,133							2,133
Dividends declared	[1]	(3,705)							(3,705)
Ending balance (in shares) at Jul. 31, 2022					36,448,695		1,821,587
Ending balance at Jul. 31, 2022		133,181			$ 3,645		$ 182	173,721	(18,808)	(25,559)
Beginning balance (in shares) at Apr. 30, 2023			36,907,242	1,821,587	36,907,242		1,821,587
Beginning balance at Apr. 30, 2023		$ 139,334			$ 3,691		$ 182	182,722	(21,702)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		22,253			22,253	[1]
Proceeds from stock options exercised	[1]	$ 246			$ 2			244
Stock-based compensation		1,554						1,554
Net earnings		2,748							2,748
Dividends declared	[1]	(3,757)							(3,757)
Ending balance (in shares) at Jul. 31, 2023			36,929,495	1,821,587	36,929,495		1,821,587
Ending balance at Jul. 31, 2023		$ 140,125			$ 3,693		$ 182	$ 184,520	$ (22,711)	$ (25,559)

[1] Amounts adjusted for rounding