Earnings Per Common Share - Basic Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total (in usd per share)	[1]	$ 0.06	$ 0.10	$ 0.12	$ 0.19
Basic weighted average common shares outstanding (in shares)		33,720	33,337	33,688	33,195
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	$ 0.22	$ 0.22
Undistributed losses (in usd per share)		(0.05)	(0.01)	(0.10)	(0.03)
Total (in usd per share)		$ 0.06	$ 0.10	$ 0.12	$ 0.19
Distributed earnings		$ 3,511	$ 3,475	$ 7,016	$ 6,926
Undistributed losses		(1,542)	(342)	(3,030)	(1,007)
Total		$ 1,969	$ 3,133	$ 3,986	$ 5,919
Basic weighted average common shares outstanding (in shares)		31,898	31,515	31,866	31,373
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	$ 0.22	$ 0.22
Undistributed losses (in usd per share)		(0.05)	(0.01)	(0.10)	(0.03)
Total (in usd per share)		$ 0.06	$ 0.10	$ 0.12	$ 0.19
Distributed earnings		$ 200	$ 201	$ 400	$ 401
Undistributed losses		(88)	(20)	(172)	(59)
Total		$ 112	$ 181	$ 228	$ 342
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 $0.06 and $0.10 for the three months ended October 31, 2022 and 2021 and $0.12 and $0.19 for the six months ended October 31, 2022 and 2021. See Note D to the Condensed Consolidated Financial Statements.