Long-Term Debt - Revolving Credit Facility (Details) - Revolving Credit Facility	6 Months Ended
Mar. 31, 2017 USD ($)	Sep. 30, 2016 USD ($)
Line of Credit Facility [Line Items]
Borrowings outstanding	$ 0	$ 0
Letters of credit outstanding	$ 0	$ 0
Triggering Event One
Line of Credit Facility [Line Items]
Debt-to-EBITDA ratio	2.25
LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.00%
Unused capacity, commitment fee percentage	0.45%
Amended Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 525,000,000
Deferred issuance cost	$ 4,000,000
Collateral test, maximum ratio	1.0
Value of company assets collateralized	$ 732,000,000
Maximum limit on issuance, letters of credit	$ 100,000,000
Overnight Revolving Credit Loans \| Prime Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.00%

Debt Instrument, Covenant, Collateral Test, Maximum Ratio

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- Definition

Maximum Limit on the issuance of letters of credit.

+ References

No definition available.

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- Definition

Ratio of Total Priority Debt (consisting principally of amounts outstanding under revolving credit facility, U.S. accounts receivable securitization and factoring programs, and third-party non-working capital foreign debt) to EBITDA Through Period End

+ References

No definition available.

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- Definition

Value as of the reporting date of Company's assets collateralized for borrowings under the revolving credit facility.

+ References

No definition available.

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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.

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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