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Identifiable Intangible Assets Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2016
Amortization | $ 22.8 | $ 22.1 | $ 21.2
Software and Software Development Costs [Member] |  |  |
Finite-Lived Intangible Asset, Useful Life | 6 years |  |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life | 2 years 9 months 18 days |  |
Amortization | $ 2.9 | 2.4 | 1.9
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months | 3.5 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Two | 3.2 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Three | 2.5 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Four | 2.0 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Five | $ 1.5 |  |
Business Combination-Related Identifiable Intangible [Member] |  |  |
Finite-Lived Intangible Asset, Useful Life | 6 years 9 months 18 days |  |
Amortization | $ 19.9 | $ 19.7 | $ 19.3
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months | 20.7 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Two | 20.7 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Three | 20.6 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Four | 20.5 |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Five | $ 20.5 |  |

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- Definition Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
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- Definition The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
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- Definition Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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