Basis of Presentation, Business and Summary of Significant Accounting Policies - Delivery Expenses, Receivable Reserves and Excess Inventory (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Trade Accounts Receivable
Reserves for uncollectible accounts, returns and cash discounts	$ 9,851	$ 8,607
Inventories
Period of inventory purchases excluded from excess inventory	12 months
Selling, general and administrative expenses
Delivery expenses classification
Delivery expenses	$ 205,019	$ 159,098	$ 128,381