Presentation and Summary of Significant Accounting Policies - Basic Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Apr. 30, 2024	Apr. 30, 2023	Apr. 30, 2022
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic weighted average common shares (in shares)		33,689	33,761	33,365
Class A Common Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings per share (in usd per share)		$ 0.44	$ 0.44	$ 0.44
Undistributed (loss) per share (in usd per share)		(0.10)	(0.14)	(0.06)
Total from continuing operations (in usd per share)	[1]	0.29	0.29	0.35
Total from discontinued operations (in usd per share)	[1]	0.05	0.01	0.03
Basic (in usd per share)	[1]	$ 0.34	$ 0.30	$ 0.38
Distributed earnings		$ 14,024	$ 14,098	$ 13,924
Undistributed loss		(3,266)	(4,342)	(1,816)
Total from continuing operations		9,079	9,430	10,975
Total from discontinued operations		1,679	327	1,131
Total		$ 10,758	$ 9,757	$ 12,106
Basic weighted average common shares (in shares)		31,867	31,939	31,543
Class B Common Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings per share (in usd per share)		$ 0.44	$ 0.44	$ 0.44
Undistributed (loss) per share (in usd per share)		(0.10)	(0.14)	(0.06)
Total from continuing operations (in usd per share)		0.34	0.30	0.38
Total from discontinued operations (in usd per share)		0	0	0
Basic (in usd per share)		$ 0.34	$ 0.30	$ 0.38
Distributed earnings		$ 802	$ 803	$ 804
Undistributed loss		(187)	(248)	(105)
Total from continuing operations		615	555	699
Total from discontinued operations		0	0	0
Total		$ 615	$ 555	$ 699
Basic weighted average common shares (in shares)		1,822	1,822	1,822

[1] Diluted per share amounts for Class A shares are shown above. Diluted per share for Class B shares under the two-class method are $0.34, $0.30 and $0.38 for the years ended April 30, 2024, 2023 and 2022, respectively. See Note 1(s) to the Consolidated Financial Statements.