Segments - Net sales by major geographic area (Details) $ in Thousands	2 Months Ended	3 Months Ended
	Jul. 31, 2018 $ / $	Jul. 31, 2019 USD ($) $ / $	Jul. 31, 2018 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales		$ 847,176	$ 778,144
Average exchange rates | $ / $	0.7652	0.7518
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales		$ 731,343	690,731
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales		$ 115,833	$ 87,413