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, 2021					35,629,566		1,821,587
Beginning 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)		678,129			678,129
Proceeds from stock options exercised		$ 7,405			$ 67			7,338
Stock-based compensation		2,910						2,910
Net earnings		9,201							9,201
Dividends declared	[1]	(11,028)							(11,028)
Ending balance (in shares) at Jan. 31, 2022					36,307,695		1,821,587
Ending balance at Jan. 31, 2022		130,879			$ 3,630		$ 182	169,740	(17,114)	(25,559)
Beginning balance (in shares) at Oct. 31, 2021					36,174,808		1,821,587
Beginning balance at Oct. 31, 2021		128,847			$ 3,617		$ 182	166,969	(16,362)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)					132,887
Proceeds from stock options exercised		1,691			$ 13			1,678
Stock-based compensation		1,093						1,093
Net earnings		2,940							2,940
Dividends declared	[2]	(3,692)							(3,692)
Ending balance (in shares) at Jan. 31, 2022					36,307,695		1,821,587
Ending balance at Jan. 31, 2022		130,879			$ 3,630		$ 182	169,740	(17,114)	(25,559)
Beginning balance (in shares) at Apr. 30, 2022			36,405,695	1,821,587	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)		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		7,554							7,554
Dividends declared	[1]	(11,132)							(11,132)
Ending balance (in shares) at Jan. 31, 2023			36,546,495	1,821,587	36,546,495		1,821,587
Ending balance at Jan. 31, 2023		134,996			$ 3,655		$ 182	177,532	(20,814)	(25,559)
Beginning balance (in shares) at Oct. 31, 2022					36,503,495		1,821,587
Beginning balance at Oct. 31, 2022		133,568			$ 3,650		$ 182	175,733	(20,438)	(25,559)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from stock options exercised (in shares)	[2]				43,000
Proceeds from stock options exercised	[2]	510			$ 5			505
Stock-based compensation		1,294						1,294
Net earnings		3,340							3,340
Dividends declared	[2]	(3,716)							(3,716)
Ending balance (in shares) at Jan. 31, 2023			36,546,495	1,821,587	36,546,495		1,821,587
Ending balance at Jan. 31, 2023		$ 134,996			$ 3,655		$ 182	$ 177,532	$ (20,814)	$ (25,559)

[1] Amounts adjusted for rounding

[2] Amounts adjusted for rounding