GOODWILL AND INTANGIBLE ASSETS (Schedule of Intangible Assets) (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Apr. 30, 2020	Jul. 31, 2019
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,028,434	$ 1,022,157	$ 967,368
Accumulated Amortization	(628,409)	(607,181)	(547,977)
Net	400,025	414,976	419,391
Reacquired franchise rights
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	365,506	365,062	350,679
Accumulated Amortization	(165,721)	(159,754)	(141,954)
Net	199,785	205,308	208,725
Customer relationships
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	314,920	314,191	300,156
Accumulated Amortization	(235,645)	(227,445)	(203,283)
Net	79,275	86,746	96,873
Internally-developed software
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	159,195	154,083	144,768
Accumulated Amortization	(115,976)	(113,698)	(111,892)
Net	43,219	40,385	32,876
Noncompete agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	41,112	41,072	40,358
Accumulated Amortization	(34,193)	(33,639)	(31,980)
Net	6,919	7,433	8,378
Franchise agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	19,201	19,201	19,201
Accumulated Amortization	(14,934)	(14,614)	(13,654)
Net	4,267	4,587	5,547
Purchased technology
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	122,700	122,700	104,700
Accumulated Amortization	(61,313)	(57,548)	(45,166)
Net	61,387	65,152	59,534
Trade name
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	5,800	5,800	5,800
Accumulated Amortization	(627)	(483)	(48)
Net	$ 5,173	5,317	5,752
Acquired assets pending final allocation
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount		48	1,706
Accumulated Amortization		0	0
Net		$ 48	$ 1,706