Goodwill and Intangible Assets - Definite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jul. 31, 2021	Apr. 30, 2021
Definite-lived intangible assets
Gross Carrying Amount	$ 705,556	$ 647,973
Accumulated Amortization	(371,276)	(358,471)
Total	$ 334,280	$ 289,502
Customer relationships
Definite-lived intangible assets
Weighted Average Amortization Period (years)	12 years 8 months 12 days	13 years 3 months 18 days
Gross Carrying Amount	$ 616,241	$ 569,255
Accumulated Amortization	(342,161)	(330,880)
Total	$ 274,080	$ 238,375
Customer relationships | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Customer relationships | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	16 years	16 years
Definite-lived tradenames
Definite-lived intangible assets
Weighted Average Amortization Period (years)	15 years 9 months 18 days	16 years 9 months 18 days
Gross Carrying Amount	$ 72,820	$ 62,084
Accumulated Amortization	(15,803)	(14,842)
Total	$ 57,017	$ 47,242
Definite-lived tradenames | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Definite-lived tradenames | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	20 years	20 years
Vendor agreements
Definite-lived intangible assets
Weighted Average Amortization Period (years)	8 years 3 months 18 days	8 years 3 months 18 days
Gross Carrying Amount	$ 6,644	$ 6,644
Accumulated Amortization	(5,574)	(5,372)
Total	$ 1,070	$ 1,272
Vendor agreements | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	8 years	8 years
Vendor agreements | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	10 years	10 years
Developed technology
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Weighted Average Amortization Period (years)	4 years 10 months 24 days	4 years 10 months 24 days
Gross Carrying Amount	$ 5,608	$ 5,699
Accumulated Amortization	(3,612)	(3,381)
Total	$ 1,996	$ 2,318
Other intangible assets
Definite-lived intangible assets
Weighted Average Amortization Period (years)	3 years 2 months 12 days	3 years 3 months 18 days
Gross Carrying Amount	$ 4,243	$ 4,291
Accumulated Amortization	(4,126)	(3,996)
Total	$ 117	$ 295
Other intangible assets | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	3 years	3 years
Other intangible assets | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years