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Investments - Additional Information (Detail) (USD $) | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 | Jun. 30, 2012 | Sep. 30, 2012
Investments Debt And Equity Securities [Abstract] |  |  |  |  |
Maturity of short-term investments |  |  | Less than one year |  | Less than one year
Maturity of long-term investments |  |  | Greater than one year |  | Greater than one year
Other-than-temporary impairment charges recognized | $ 0 | $ 0 | $ 0 | $ 0 |

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- Definition Maturity of long-term investments. + References No definition available. + Details
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- Definition Maturity of short-term investments. + References No definition available. + Details
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- Details
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- Definition The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -URI http://asc.fasb.org/extlink&oid=27724398&loc=SL6284393-111563 + Details
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