Other Accrued Expenses and Current Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2017	Apr. 30, 2016
Other Accrued Expenses and Current Liabilities
Insurance related liabilities	$ 11,027	$ 8,340
Sales taxes payable	8,920	9,297
Contingent consideration	5,708	7,265
Accrued rebates	3,041	2,054
Real estate and personal property taxes	1,686	1,431
Accrued professional services fees	872	1,741
Accrued interest	721	678
Deferred revenue	573	626
Accrued franchise tax	224	271
Income taxes payable	216	5,444
Other	4,903	4,667
Other accrued expenses and current liabilities	$ 37,891	$ 41,814