Segments - Net Sales, Adjusted EBITDA and Certain Other Measures (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Segment Reporting Information [Line Items]
Net sales	$ 932,203	$ 751,191	$ 812,856	$ 802,573	$ 770,850	$ 761,352	$ 861,929	$ 847,176	$ 3,298,823	$ 3,241,307	$ 3,116,032
Gross Profit	293,850	$ 243,324	$ 265,071	$ 260,458	251,594	$ 253,473	$ 284,493	$ 273,654	1,062,703	1,063,214	1,004,119
Depreciation and Amortization									108,125	116,533	117,459
Adjusted EBITDA									319,371	299,759	295,669
Total Assets	2,483,898				2,324,454				2,483,898	2,324,454	2,194,017
Geographic divisions
Segment Reporting Information [Line Items]
Net sales									3,263,893	3,213,938	3,090,314
Gross Profit									1,051,741	1,053,555	994,981
Depreciation and Amortization									106,152	114,279	114,558
Adjusted EBITDA									316,774	297,646	293,190
Total Assets	2,459,344				2,299,880				2,459,344	2,299,880	2,169,981
Other
Segment Reporting Information [Line Items]
Net sales									34,930	27,369	25,718
Gross Profit									10,962	9,659	9,138
Depreciation and Amortization									364	233	220
Adjusted EBITDA									2,597	2,113	2,479
Total Assets	20,339				18,745				20,339	18,745	16,897
Corporate
Segment Reporting Information [Line Items]
Net sales									0	0	0
Gross Profit									0	0	0
Depreciation and Amortization									1,609	2,021	2,681
Adjusted EBITDA									0	0	0
Total Assets	$ 4,215				$ 5,829				$ 4,215	$ 5,829	$ 7,139