Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 472	$ 249	$ 259
Additions (Reductions) Charged to Cost and Expenses	182	323	72
Other	0	0	0
Deductions	(323)	(100)	(82)
Balance at End of Year	331	472	249
Reserve for Cash Discounts [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	1,171	1,451	1,627
Additions (Reductions) Charged to Cost and Expenses	19,109	16,810	16,994
Other	0	0	0
Deductions	(18,444)	(17,090)	(17,170)
Balance at End of Year	1,836	1,171	1,451
Reserve for Sales Returns and Allowances [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	4,541	4,545	4,381
Additions (Reductions) Charged to Cost and Expenses	22,298	17,049	11,867
Other	0	0	0
Deductions	(19,685)	(17,053)	(11,703)
Balance at End of Year	$ 7,154	$ 4,541	$ 4,545