Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Allowances for Accounts Receivable
Allowance Rollforward
Balance at beginning of period	$ (6,282)	$ (5,141)	$ (6,432)
Provision / Additions charged to costs and expenses	(1,588)	(1,774)	(2,348)
Charged to other accounts	(2,714)	(477)	938
Deductions	1,238	1,110	2,701
Balance at end of period	(9,346)	(6,282)	(5,141)
Valuation Allowance on Deferred Tax Assets
Allowance Rollforward
Balance at beginning of period	(11,768)	(10,183)	(1,112)
Provision / Additions charged to costs and expenses	(1,248)	(1,585)	(9,071)
Deductions	1,297	0	0
Balance at end of period	$ (11,719)	$ (11,768)	$ (10,183)