Segments - Net Sales, Adjusted EBITDA and Certain Other Measures (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Segment information
Net sales	$ 770,850	$ 761,352	$ 861,929	$ 847,176	$ 780,149	$ 723,902	$ 833,837	$ 778,144	$ 3,241,307	$ 3,116,032	$ 2,511,469
Gross Profit	251,594	$ 253,473	$ 284,493	$ 273,654	256,927	$ 234,226	$ 268,150	$ 244,816	1,063,214	1,004,119	818,576
Depreciation and Amortization									116,533	117,459	65,530
Adjusted EBITDA									299,759	295,669	199,258
Total assets	2,288,782				2,149,554				2,288,782	2,149,554	1,454,511
Geographic divisions
Segment information
Net sales									3,213,938	3,090,314	2,487,557
Gross Profit									1,053,555	994,981	809,884
Depreciation and Amortization									114,279	114,558	64,491
Adjusted EBITDA									297,646	293,190	196,903
Total assets	2,264,208				2,125,518				2,264,208	2,125,518	1,434,371
Other.
Segment information
Net sales									27,369	25,718	23,912
Gross Profit									9,659	9,138	8,692
Depreciation and Amortization									233	220	242
Adjusted EBITDA									2,113	2,479	2,355
Total assets	18,745				16,897				18,745	16,897	12,854
Corporate
Segment information
Depreciation and Amortization									2,021	2,681	797
Total assets	$ 5,829				$ 7,139				$ 5,829	$ 7,139	$ 7,286