Earnings Per Common Share - Basic Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic (in usd per share)	[1]	$ 0.12	$ 0.09	$ 0.22	$ 0.21
Total from discontinued operations (in usd per share)	[1]	0	0	0.05	0.01
Total (in usd per share)	[1]	$ 0.12	$ 0.09	$ 0.27	$ 0.22
Basic weighted average common shares outstanding (in shares)		33,292	33,759	33,842	33,711
Class A Common Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings (in usd per share)		$ 0.11	$ 0.11	$ 0.33	$ 0.33
Undistributed losses (in usd per share)		0.01	(0.02)	(0.06)	(0.11)
Basic (in usd per share)		0.12	0.09	0.22	0.21
Total from discontinued operations (in usd per share)		0	0	0.05	0.01
Total (in usd per share)		$ 0.12	$ 0.09	$ 0.27	$ 0.22
Distributed earnings		$ 3,454	$ 3,515	$ 10,568	$ 10,532
Undistributed losses		410	(472)	(1,864)	(3,545)
Total from continuing operations		3,864	2,998	6,892	6,664
Total from discontinued operations		0	45	1,812	323
Total		$ 3,864	$ 3,043	$ 8,704	$ 6,987
Basic weighted average common shares outstanding (in shares)		31,470	31,937	32,020	31,890
Class B Common Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings (in usd per share)		$ 0.11	$ 0.11	$ 0.33	$ 0.33
Undistributed losses (in usd per share)		0.01	(0.02)	(0.06)	(0.11)
Basic (in usd per share)		0.12	0.09	0.27	0.22
Total from discontinued operations (in usd per share)		0	0	0	0
Total (in usd per share)		$ 0.12	$ 0.09	$ 0.27	$ 0.22
Distributed earnings		$ 200	$ 201	$ 601	$ 601
Undistributed losses		24	(27)	(106)	(202)
Total from continuing operations		224	174	495	399
Total from discontinued operations		0	0	0	0
Total		$ 224	$ 174	$ 495	$ 399
Basic weighted average common shares outstanding (in shares)		1,822	1,822	1,822	1,822

[1] Basic per share amounts are the same for Class A and Class B shares. Diluted per share amounts for Class A shares are shown above. Diluted earnings per share for Class B shares under the two-class method are $0.12 and $0.09 for the three months ended January 31, 2024 and 2023, and $0.27 and $0.22 for the nine months ended January 31, 2024 and 2023. See Note D to the condensed consolidated financial statements.