Segments - Net Sales, Adjusted EBITDA and Certain Other Measures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	May 01, 2019
Segment information
Net sales	$ 861,929	$ 833,837	$ 1,709,105	$ 1,611,981
Gross Profit	284,493	268,150	558,147	512,966
Depreciation and Amortization	29,518	30,787	58,793	57,109
Adjusted EBITDA	89,905	87,145	173,493	162,417
Operating lease right-of-use assets	107,624		107,624
Geographic divisions
Segment information
Net sales	854,853	827,198	1,695,010	1,598,748
Gross Profit	281,900	265,815	553,254	508,390
Depreciation and Amortization	29,024	30,062	57,956	55,916
Adjusted EBITDA	89,171	86,450	172,254	161,044
Operating lease right-of-use assets					$ 113,300
Other.
Segment information
Net sales	7,076	6,639	14,095	13,233
Gross Profit	2,593	2,335	4,893	4,576
Depreciation and Amortization	55	55	108	113
Adjusted EBITDA	734	695	1,239	1,373
Operating lease right-of-use assets					300
Corporate
Segment information
Depreciation and Amortization	$ 439	$ 670	$ 729	$ 1,080
Operating lease right-of-use assets					$ 5,200