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Derivative Financial Instruments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 9 Months Ended | 60 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2018 | Mar. 31, 2018 | Jun. 30, 2017 | Mar. 31, 2017 | Mar. 31, 2018 | Mar. 31, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Sep. 30, 2021 | Sep. 30, 2017 | Sep. 30, 2016
Derivative [Line Items] |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Repurchase Date |  |  |  |  |  |  | Jun. 12, 2018 |  |  |  |
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 |  | 0.0 |  | $ 0.5 | 0.6 | $ 1.5 |  |  |  |  |
Other noncurrent liabilities |  | 0.6 |  |  | $ 0.6 |  |  |  |  | $ 1.3 |
Gain (Loss) on Discontinuation of Interest Rate Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net | $ 2.4 |  | $ 0.0 |  |  |  | $ 2.4 | $ 0.0 |  |  |
Secured Debt [Member] |  |  |  |  |  |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |  |  |  |  |  |
Long-term Debt, Gross | $ 500.0 |  |  |  |  |  | $ 500.0 |  |  |  |
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 Date on which a hedging relationship begins. + References No definition available. + Details
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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 Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + 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(a)(1)) -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 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
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- Definition Amount of the hedged item as of the balance sheet date related to the derivative. For example, the hedged balance on a debt instrument. + References No definition available. + Details
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- Definition Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract. + References No definition available. + 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 Fair value as of the balance sheet date of all foreign currency derivative liabilities not designated as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959 + Details
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- Definition The amount of net gain (loss) reclassified into earnings when interest rate cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994 + Details
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