Segments - Net sales by major geographic area (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 1,042,076	$ 802,573
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	862,790	679,321
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 179,286	$ 123,252