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, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total (in usd per share)	[1]	$ 0.10	$ 0.09	$ 0.22	$ 0.28
Basic weighted average common shares outstanding (in shares)		33,759	33,490	33,711	33,293
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)	(0.11)	(0.05)
Total (in usd per share)		$ 0.10	$ 0.09	$ 0.22	$ 0.28
Distributed earnings		$ 3,515	$ 3,488	$ 10,532	$ 10,426
Undistributed losses		(355)	(708)	(3,385)	(1,727)
Total		$ 3,160	$ 2,780	$ 7,147	$ 8,699
Basic weighted average common shares outstanding (in shares)		31,937	31,668	31,890	31,471
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)	(0.11)	(0.05)
Total (in usd per share)		$ 0.10	$ 0.09	$ 0.22	$ 0.28
Distributed earnings		$ 201	$ 201	$ 601	$ 602
Undistributed losses		(21)	(41)	(194)	(100)
Total		$ 180	$ 160	$ 407	$ 502
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 $0.10 and $0.09 for the three months ended January 31, 2023 and 2022 and $0.22 and $0.28 for the nine months ended January 31, 2023 and 2022. See Note D to the Condensed Consolidated Financial Statements.