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Derivative Financial Instruments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 60 Months Ended |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Mar. 31, 2018 | Mar. 31, 2017 | Sep. 30, 2021 | Sep. 30, 2017 | Sep. 30, 2016
Derivative [Line Items] |  |  |  |  |  |  |
Other noncurrent assets | $ 1.5 |  | $ 1.5 |  |  | $ 0.0 |
Interest Rate Derivative Assets, at Fair Value | 1.5 |  | 1.5 |  |  | 0.0 |
Other current liabilities | $ 0.0 |  | $ 0.0 |  |  | 1.2 |
Derivative, Cap Interest Rate |  |  |  |  |  |  | 0.75%
Derivative, Fixed Interest Rate | 2.341% |  | 2.341% |  |  |  |
Derivative, Amount of Hedged Item | $ 150.0 |  | $ 150.0 |  |  |  |
Other noncurrent liabilities | 0.0 |  | 0.0 |  |  | 1.3 |
Interest Rate Derivatives, at Fair Value, Net | 0.0 |  | 0.0 |  |  | 2.5 |
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net | 0.2 | $ 0.5 | 0.6 | $ 1.1 |  |  |
Other noncurrent liabilities | 1.0 |  | 1.0 |  |  | $ 1.3 |
Secured Debt [Member] |  |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |  |
Long-term Debt, Gross | $ 500.0 |  | $ 500.0 |  |  |  |
Debt Instrument, Interest Rate, Effective Percentage | 4.78% |  | 4.78% |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  | 25000.00% |  |  |  |
Scenario, Forecast [Member] |  |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |  |
HedgePeriodStart |  |  |  |  | Sep. 30, 2016 |  |
Derivative, Maturity Date |  |  |  |  | Sep. 30, 2021 |  |
Cash Flow Hedging [Member] | Secured Debt [Member] |  |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |  |
Long-term Debt, Gross | $ 150.0 |  | $ 150.0 |  |  |  |
Debt Instrument, Interest Rate, Effective Percentage | 4.841% |  | 4.841% |  |  |  |

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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
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- Definition The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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