Commitments And Contingencies (Narrative) (Details) - USD ($)	12 Months Ended			108 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017
Commitments And Contingencies [Line Items]
POM Maximum per Tax Return	$ 10,000
Standard guarantee accrual amount	$ 9,400,000	$ 6,800,000		$ 6,800,000
Document Fiscal Year Focus	2018
Other Commitment, Percentage of Participation Interest Required to be Purchased at Par	90.00%
Commitments to Extend Credit, Total	$ 40,900,000
Contingent acquisition liabilities, Carrying Amount	12,060,000	10,428,000		10,428,000
Remaining franchise equity lines of credit-undrawn commitment	20,200,000
Amounts deferred for new extended service plans issued		120,691,000
Revenue recognized on previous deferrals		(113,810,000)
Deferred revenue		211,223,000	$ 204,342,000	211,223,000
Obligation under deferred compensation plans	23,300,000	25,200,000		25,200,000
Rent expense	$ 245,900,000	236,200,000	$ 228,500,000
Claims received for loans				2,600,000,000
Minimum
Commitments And Contingencies [Line Items]
Term of operating leases, years	3 years
Maximum
Commitments And Contingencies [Line Items]
Term of operating leases, years	5 years
Refund Advance [Member]
Commitments And Contingencies [Line Items]
Pre e-File Guaranty	$ 10,000,000
Loss Contingency Accrual	1,600,000	700,000		700,000
Guaranty for Loan Losses	57,000,000
Peace of Mind
Commitments And Contingencies [Line Items]
Amounts deferred for new extended service plans issued	122,650,000
Revenue recognized on previous deferrals	(115,599,000)
Deferred revenue	218,274,000	$ 211,223,000		$ 211,223,000
Geographic Distribution, Domestic [Member]
Commitments And Contingencies [Line Items]
Additional tax assessment limit per client	6,000
Non-US [Member]
Commitments And Contingencies [Line Items]
Additional tax assessment limit per client	$ 3,000