Other Accrued Expenses and Current Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Apr. 30, 2018
Other Accrued Expenses and Current Liabilities
Insurance related liabilities	$ 14,110	$ 11,432
Contingent consideration	13,073	1,917
Sales taxes payable	10,448	9,864
Income taxes payable	14,063
Customer rebates payable	7,944	3,640
Reserve for sales returns	4,701
Real estate and personal property taxes	2,010	1,823
Derivative liability		5,108
Other	13,499	11,362
Total other accrued expenses and current liabilities	$ 79,848	$ 45,146