Goodwill And Intangible Assets (Schedule Of Intangible Assets) (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Apr. 30, 2018
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	$ 872,195	$ 843,073
Accumulated Amortization	(529,702)	(469,092)
Net	342,493	373,981
Reacquired franchise rights
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	350,410	339,779
Accumulated Amortization	(136,345)	(113,856)
Net	214,065	225,923
Customer relationships
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	274,838	256,137
Accumulated Amortization	(195,174)	(164,005)
Net	79,664	92,132
Internally-developed software
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	139,239	140,255
Accumulated Amortization	(109,885)	(111,734)
Net	29,354	28,521
Noncompete agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	33,376	32,899
Accumulated Amortization	(31,446)	(29,673)
Net	1,930	3,226
Franchise agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	19,201	19,201
Accumulated Amortization	(13,334)	(12,054)
Net	5,867	7,147
Purchased technology
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	54,700	54,700
Accumulated Amortization	(43,518)	(37,770)
Net	11,182	16,930
Acquired assets pending final allocation
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	431	102
Accumulated Amortization	0	0
Net	$ 431	$ 102