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Assets and Liabilities, at Fair Value - Available for Sale Securities in OCI (Details) - USD ($) $ in Millions | 12 Months Ended
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Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2013
Assets and Liabilities, at Fair Value [Abstract] |  |  |
Equity Investments in Exchange Stock - Cost | $ 3.7 | $ 3.7 |
Equity Investments in Exchange Stock - Fair Value | 5.6 | 4.8 |
Proceeds from Sale of Exchange Stock | 2.1 |  |
Gain (Loss) on Disposition of Exchange Stock | 1.2 |  |
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax - AFS securities | 3.3 | (3.3) |
Deferred Tax Liabilities, Accumulated Other Comprehensive Income - AFS Securities | 2.0 |  |
Proceeds from Shares of Exchanges Sold |  | 1.5 |
Gain (Loss) on Sale of Exchange Shares |  | 0.9 |
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax | 5.4 | 0.1 | $ 8.3
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax | $ 2.7 | $ 0.2 | $ 0.6

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- Definition Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax - LME represents accumulated appreciation or loss, net of tax, in value of the total available-for-sale securities at the end of an accounting period. + References No definition available. + Details
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- Definition Deferred Tax Liabilities, Accumulated Other Comprehensive Income - LME Shares + References No definition available. + Details
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- Definition Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=51824106&loc=d3e2443-110228 + Details
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- Definition Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e689-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580 + Details
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