Investments (Narrative) (Details) (USD $)	12 Months Ended
Apr. 30, 2013 securities	Apr. 30, 2012	Apr. 30, 2011
Investments, Debt and Equity Securities [Abstract]
Available-For-Sale Securities, Continuous Unrealized Loss Position, Number of Securities	0
Period Over Which Contractual Maturities of AFS Debt Securities Occurs	31 years
Proceeds from Sale of available-for-sale securities	$ 6,200,000	$ 8,400,000
Available-for-sale Securities, Gross realized gains	200,000	14,000
Other-than-temporary impairments of AFS securities			1,900,000
Held-to-maturity Securities	$ 1,900,000	$ 1,900,000

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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+ Details

- Definition

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References+ Details

- Definition

The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

+ References

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+ Details