Segments - Net sales by major geographic area (Details) $ in Thousands	3 Months Ended		5 Months Ended	6 Months Ended
	Oct. 31, 2019 USD ($) $ / $	Oct. 31, 2018 USD ($) $ / $	Oct. 31, 2018 $ / $	Oct. 31, 2019 USD ($) $ / $	Oct. 31, 2018 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 861,929	$ 833,837		$ 1,709,105	$ 1,611,981
Average exchange rates | $ / $	0.7547	0.7697	0.7679	0.7533
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 744,134	$ 706,347		$ 1,475,477	1,397,078
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 117,795	$ 127,490		$ 233,628	$ 214,903