Fair Value Fair Value Of Financial Instruments (Summary Of Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments) (Details) - USD ($) $ in Thousands	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and cash equivalents, Carrying Amount	$ 896,801	$ 2,007,190	$ 2,185,307	$ 1,747,584
Cash and cash equivalents, Estimated Fair Value	896,801	2,007,190
Cash and cash equivalents - restricted, Carrying Amount	104,110	91,972
Cash and cash equivalents - restricted, Estimated Fair Value	104,110	91,972
Receivables, net - short-term, Carrying Amount	153,116	167,964
Receivables, net - short-term, Estimated Fair Value	153,116	167,964
Mortgage loans held for investment, less allowance for loan losses of $5,518 and $7,886	202,385	239,338
Mortgage loans held for investment, net, Estimated Fair Value	190,503	190,196
Investments in available-for-sale securities, Estimated Fair Value	1,133	441,709
Receivables, net - long-term, Carrying Amount	60,407	80,867
Receivables, net - long-term, Estimated Fair Value	60,407	80,867
Deposits, Carrying Amount	0	744,699
Deposits, Estimated Fair Value	0	737,261
Long-term borrowings, Carrying Amount	1,502,751	506,088
Long-term borrowings, Estimated Fair Value	1,566,098	556,769
Contingent acquisition liabilities, Carrying Amount	8,657	10,667
Contingent acquisition liabilities, Estimated Fair Value	$ 8,657	$ 10,667