Earnings Per Common Share - Diluted Earnings per Share for Class B Common Shares Using Two-Class Method (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Oct. 31, 2023	Oct. 31, 2022	Oct. 31, 2023	Oct. 31, 2022
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Basic weighted average common shares outstanding (in shares)		34,071	33,720	34,113	33,688
Diluted EPS for class B common shares (in shares)		34,094	34,072	34,127	34,040
Basic EPS (in usd per share)	[1]	$ 0.07	$ 0.06	$ 0.15	$ 0.12
Diluted EPS (in usd per share)	[1]	$ 0.07	$ 0.06	$ 0.15	$ 0.12
Class B Common Shares
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Undistributed and distributed earnings		$ 126	$ 113	$ 273	$ 224
Reallocation of undistributed earnings/losses from Class A Common Shares to Class B Common Shares		1	1	0	2
Diluted EPS, Net earnings		$ 127	$ 114	$ 273	$ 226
Basic weighted average common shares outstanding (in shares)		1,822	1,822	1,822	1,822
Diluted EPS for class B common shares (in shares)		1,822	1,822	1,822	1,822
Basic EPS (in usd per share)		$ 0.07	$ 0.06	$ 0.15	$ 0.12
Diluted EPS (in usd per share)		$ 0.07	$ 0.06	$ 0.15	$ 0.12

[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 $0.07 and $0.06 for the three months ended October 31, 2023 and 2022, and $0.15 and $0.12 for the six months ended October 31, 2023 and 2022. See Note D to the condensed consolidated financial statements.