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Income Taxes (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2015
Income Tax Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |
Income tax expense | $ 1.1 | $ 2.3 | $ 3.3 | $ 2.1 | $ 2.4 | $ 6.8 | $ 5.5 | $ 3.3 | $ 8.8 | $ 18.0 | $ 22.4
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax |  |  |  |  |  |  |  |  | 0.0 | 0.0 | (0.4)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Tax |  |  |  |  |  |  |  |  | 1.0 | 0.2 | (0.8)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation |  |  |  |  |  |  |  |  | (0.1) | (0.8) | (0.5)
Other Comprehensive Income (Loss), Tax |  |  |  |  |  |  |  |  | 9.9 | 17.4 | 20.7
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense |  |  |  |  |  |  |  |  | 0.0 |  |
Operating Loss Carryforwards | 30.1 |  |  |  | 15.7 |  |  |  | 30.1 | 15.7 |
Deferred Tax Assets, Operating Loss Carryforwards, Domestic | 21.9 |  |  |  | 12.4 |  |  |  | 21.9 | 12.4 |
Deferred Tax Assets, Net of Valuation Allowance, Operating Loss Carryforwards, State and Local | 4.4 |  |  |  |  |  |  |  | 4.4 |  |
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax | 1.3 |  |  |  |  |  |  |  | 1.3 |  |
Deferred Tax Assets, Valuation Allowance | 4.0 |  |  |  | 3.6 |  |  |  | 4.0 | 3.6 |
Valuation Allowance, Deferred Tax Asset, Change in Amount |  |  |  |  |  |  |  |  | 0.4 |  |
Income (Loss) from Continuing Operations before Income Taxes, Domestic |  |  |  |  |  |  |  |  | (24.7) | (9.7) | $ 16.5
Deferred Tax Liabilities, Gross | 4.9 |  |  |  |  |  |  |  | 4.9 |  |
Deferred Tax Liabilities, Unrealized Gains on Trading Securities | 3.1 |  |  |  |  |  |  |  | 3.1 |  |
Undistributed Earnings of Foreign Subsidiaries | $ 321.3 |  |  |  | $ 294.3 |  |  |  | $ 321.3 | $ 294.3 |

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- Definition Deferred Tax Assets, Net of Valuation Allowance, Operating Loss Carryforwards, State and Local - Amount after allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards. + References No definition available. + Details
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- Definition Taxable Income (Loss) from Continuing Operations before Income Taxes, Domestic - The taxable portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations. + References No definition available. + Details
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- Definition Amount of increase in additional paid in capital (APIC) resulting from a tax benefit associated with share-based compensation plan other than an employee stock ownership plan (ESOP). Includes, but is not limited to, excess tax benefit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 740 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=79981250&loc=d3e23524-113945 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319 + Details
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- Definition Amount of deferred tax liability attributable to taxable temporary differences classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28680-109314 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319 + Details
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