Business, Basis of Presentation and Summary of Significant Accounting Policies - Selling, General and Administrative Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Delivery expenses classification
Cost of sales (exclusive of depreciation and amortization shown separately below)	$ 2,111,913	$ 1,692,893	$ 1,560,575
Delivery | Selling, general and administrative expenses
Delivery expenses classification
Cost of sales (exclusive of depreciation and amortization shown separately below)	$ 225,600	$ 228,000	$ 205,000