Goodwill And Intangible Assets (Schedule Of Intangible Assets) (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Apr. 30, 2017	Jul. 31, 2016
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	$ 817,028	$ 812,133	$ 766,739
Accumulated Amortization	(423,056)	(402,769)	(346,830)
Net	393,972	409,364	419,909
Reacquired franchise rights
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	331,371	331,150	319,545
Accumulated Amortization	(96,600)	(90,877)	(72,977)
Net	234,771	240,273	246,568
Customer relationships
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	235,413	234,603	206,606
Accumulated Amortization	(140,881)	(133,207)	(110,696)
Net	94,532	101,396	95,910
Internally-developed software
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	143,206	139,709	132,897
Accumulated Amortization	(112,894)	(108,379)	(99,873)
Net	30,312	31,330	33,024
Noncompete agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	32,498	32,408	31,492
Accumulated Amortization	(28,143)	(27,559)	(26,045)
Net	4,355	4,849	5,447
Franchise agreements
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	19,201	19,201	19,201
Accumulated Amortization	(11,094)	(10,774)	(9,814)
Net	8,107	8,427	9,387
Purchased technology
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	54,700	54,700	54,700
Accumulated Amortization	(33,444)	(31,973)	(27,425)
Net	21,256	22,727	27,275
Acquired assets pending final allocation
Goodwill and Intangible Assets [Line Items]
Gross Carrying Amount	639	362	2,298
Accumulated Amortization	0	0	0
Net	$ 639	$ 362	$ 2,298