Fair Value Measurement Fair Value Of Financial Instruments (Summary Of Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2010
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and cash equivalents, Carrying Amount	$ 1,747,584	$ 1,944,334	$ 1,677,844	$ 1,804,045
Cash and cash equivalents, Estimated Fair Value	1,747,584
Cash and cash equivalents - restricted, Carrying Amount	117,837	48,100
Cash and cash equivalents - restricted, Estimated Fair Value	117,837
Receivables, net - short-term, Carrying Amount	206,835	193,858
Receivables, net - short-term, Estimated Fair Value	206,810
Mortgage loans held for investment, less allowance for loan losses of $14,314 and $26,540	338,789	406,201
Mortgage loans held for investment, net, Estimated Fair Value	210,858
Investments in available-for-sale securities, Carrying Amount	486,876	371,315
Investments in available-for-sale securities, Estimated Fair Value	486,876	372,352
Receivables, net - long-term, Carrying Amount	125,048
Receivables, net - long-term, Estimated Fair Value	134,283
Note receivable (including interest), Carrying Amount	60,352
Note receivable (including interest), Estimated Fair Value	69,472
Deposits, Carrying Amount	938,331
Deposits, Estimated Fair Value	934,019
Long-term borrowings, Carrying Amount	906,680	1,040,549
Long-term borrowings, Estimated Fair Value	964,630
Contingent acquisition liabilities, Carrying Amount	11,277
Cusiness Combination, Contingent Consideration, at Fair Value	11,277
Level 1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and cash equivalents, Carrying Amount		1,944,334
Cash and cash equivalents, Estimated Fair Value		1,944,334
Cash and cash equivalents - restricted, Carrying Amount		48,100
Cash and cash equivalents - restricted, Estimated Fair Value		48,100
Receivables, net - short-term, Carrying Amount		193,858
Receivables, net - short-term, Estimated Fair Value		193,858
Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Mortgage loans held for investment, less allowance for loan losses of $14,314 and $26,540		406,201
Mortgage loans held for investment, net, Estimated Fair Value		248,535
Note receivable (including interest), Carrying Amount		55,444
Note receivable (including interest), Estimated Fair Value		55,444
Long-term borrowings, Carrying Amount		1,040,549
Long-term borrowings, Estimated Fair Value		1,077,223
Contingent acquisition liabilities, Carrying Amount		6,838
Cusiness Combination, Contingent Consideration, at Fair Value		6,838
Level 2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments in available-for-sale securities, Carrying Amount		372,352
Investments in available-for-sale securities, Estimated Fair Value		372,352
Level 1 And 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Receivables, net - long-term, Carrying Amount		127,468
Receivables, net - long-term, Estimated Fair Value		127,468
Deposits, Carrying Amount		833,047
Deposits, Estimated Fair Value		$ 831,251