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		$ 132,041			$ 3,641		$ 182	$ 171,948	$ (18,171)	$ (25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		140,800			140,800	[1]
Proceeds from stock options exercised	[1]	$ 1,654			$ 14			1,640
Stock-based compensation		3,944						3,944
Net earnings		7,386							7,386
Dividends declared	[1]	(11,132)							(11,132)
Ending balance (in shares) at Jan. 31, 2023					36,546,495		1,821,587
Ending balance at Jan. 31, 2023		133,893			$ 3,655		$ 182	177,532	(21,917)	(25,559)
Beginning balance (in shares) at Oct. 31, 2022					36,503,495		1,821,587
Beginning balance at Oct. 31, 2022		132,588			$ 3,650		$ 182	175,733	(21,418)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)					43,000
Proceeds from stock options exercised		510			$ 5			505
Stock-based compensation		1,294						1,294
Net earnings		3,217							3,217
Dividends declared	[1]	(3,716)							(3,716)
Ending balance (in shares) at Jan. 31, 2023					36,546,495		1,821,587
Ending balance at Jan. 31, 2023		133,893			$ 3,655		$ 182	177,532	(21,917)	(25,559)
Beginning balance (in shares) at Apr. 30, 2023			32,318,610	1,821,587	36,907,242		1,821,587
Beginning balance at Apr. 30, 2023		$ 138,288			$ 3,691		$ 182	182,722	(22,748)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)		26,253			26,253	[1]
Proceeds from stock options exercised	[1]	$ 291			$ 2			289
Stock-based compensation		4,720						4,720
Purchases of common stock		(10,235)	$ (35,800)							(10,235)
Net earnings		9,199							9,199
Dividends declared	[1]	(11,169)							(11,169)
Ending balance (in shares) at Jan. 31, 2024			31,398,542	1,821,587	36,933,495		1,821,587
Ending balance at Jan. 31, 2024		131,094			$ 3,693		$ 182	187,731	(24,718)	(35,794)
Beginning balance (in shares) at Oct. 31, 2023					36,929,495		1,821,587
Beginning balance at Oct. 31, 2023		134,450			$ 3,693		$ 182	186,100	(25,152)	(30,373)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)	[1]				4,000
Proceeds from stock options exercised	[1]	45						45
Stock-based compensation		1,586						1,586
Purchases of common stock		(5,421)								(5,421)
Net earnings		4,088							4,088
Dividends declared		(3,654)							(3,654)
Ending balance (in shares) at Jan. 31, 2024			31,398,542	1,821,587	36,933,495		1,821,587
Ending balance at Jan. 31, 2024		$ 131,094			$ 3,693		$ 182	$ 187,731	$ (24,718)	$ (35,794)

[1] Amounts adjusted for rounding