Note 7 - Investments in U.S. Treasury Notes and Bills and Marketable Securities (Detail) (USD $)	3 Months Ended	9 Months Ended
Jun. 30, 2012	Jun. 30, 2012	Sep. 30, 2011
Available-for-sale Securities, Gross Unrealized Gain (Loss)	$ 49,710,000	$ 49,710,000	$ 24,532,000
Available-for-sale Securities, Gross Unrealized Gains	50,990,000	50,990,000	28,983,000
Available-for-sale Securities, Gross Unrealized Losses	1,280,000	1,280,000	4,451,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities	2,855,000	2,855,000
undefined		$ 1,720,000
Maximum [Member]
Available-for-sale Securities, Debt Maturities, Date		Dec. 31, 2008

After-tax amount of the write-down of equity security (stocks) costs and are recognized in earnings

No definition available.

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- Definition

Date of maturity of a debt security categorized as neither trading nor held-to-maturity, in CCYY-MM-DD format.

+ References

No definition available.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The net amount of gross unrealized gains (losses) for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (d)

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- Definition

This item represents the gross unrealized losses for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

+ References

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-Name FASB Staff Position (FSP)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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