Consolidated Balance Sheets (Parenthetical) $ in Thousands	12 Months Ended
	Apr. 30, 2022 USD ($) $ / shares shares	Apr. 30, 2021 USD ($) $ / shares shares
Trade accounts receivable, allowance for doubtful accounts | $	$ 423	$ 430
Class A treasury stock shares	4,588,632	4,588,632
Class A Common Shares
Common stock, par value (in usd per share) | $ / shares	$ 0.10	$ 0.10
Common Stock, shares authorized	50,000,000	50,000,000
Common Stock, shares issued	36,405,695	35,629,566
Common Stock, shares issued, net	31,817,063	31,040,934
Common Stock, shares outstanding	36,405,695	35,629,566
Common Stock, shares outstanding, net	31,817,063	31,040,934
Class B Common Shares
Common stock, par value (in usd per share) | $ / shares	$ 0.10	$ 0.10
Common Stock, shares authorized	10,000,000	10,000,000
Common Stock, shares issued	1,821,587	1,821,587
Common Stock, shares outstanding	1,821,587	1,821,587
Share conversion ratio	1	1