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		9 Months Ended
		Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2024	Jan. 31, 2023
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Basic weighted average common shares outstanding (in shares)		33,292	33,759	33,842	33,711
Diluted EPS for class B common shares (in shares)		33,337	33,965	33,866	34,006
Basic EPS (in usd per share)	[1]	$ 0.12	$ 0.09	$ 0.27	$ 0.22
Diluted EPS (in usd per share)	[1]	$ 0.12	$ 0.09	$ 0.27	$ 0.22
Class B Common Shares
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Undistributed and distributed earnings		$ 224	$ 174	$ 495	$ 399
Reallocation of undistributed earnings/losses from Class A Common Shares to Class B Common Shares		0	1	0	2
Diluted EPS, Net earnings		$ 224	$ 175	$ 495	$ 401
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)		$ 0.12	$ 0.09	$ 0.27	$ 0.22
Diluted EPS (in usd per share)		$ 0.12	$ 0.09	$ 0.27	$ 0.22

[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.