Face (par) amount of debt instrument at time of issuance.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Topic 835
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-Section 45
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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

Amount, before 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

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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))
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ 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

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
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- Definition

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

+ References

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- Definition

The net cash inflow or cash outflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is collateralized (backed by pledge, mortgage or other lien in the entity's assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
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- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

The cash outflow for the settlement of obligation drawn from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

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Debt - Credit Agreement (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Debt - Credit Agreement (Details) - USD ($) $ in Millions	Aug. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Prior Term Loan Facility
Debt Instrument [Line Items]
Credit agreement borrowings		$ 0.0	$ 0.0	$ 500.0
Credit agreement repayments		$ (468.7)	(21.9)	(9.4)
Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Line of credit facility, facility fee		0.125%
Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Line of credit facility, facility fee		0.30%
Credit Agreement \| Credit Agreement — Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,750.0
Debt issuance costs	5.7
Proceeds from (Repayments of) Lines of Credit		$ 109.5
Borrowings from lines of credit			0.0
Repayments of lines of credit			0.0
Borrowings outstanding		0.0	0.0
Credit Agreement \| Credit Agreement — Revolving Credit Facility \| Prior Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	1,250.0
Credit Agreement \| Credit Agreement — Term Loan Facility \| Term Loan Facility
Debt Instrument [Line Items]
Debt instrument, face amount	250.0
Credit agreement borrowings	250.0
Credit agreement repayments	(453.1)	(1.6)
Credit Agreement \| Credit Agreement — Term Loan Facility \| Prior Term Loan Facility
Debt Instrument [Line Items]
Debt instrument, face amount	500.0
Credit agreement repayments		$ (468.7)	$ (21.9)
Credit Agreement \| Prior Revolving Credit Facility \| Prior Revolving Credit Facility
Debt Instrument [Line Items]
Proceeds from (Repayments of) Lines of Credit				$ 48.0
Credit Agreement \| Prior Term Loan Facility \| Term Loan Facility
Debt Instrument [Line Items]
Debt instrument, face amount	$ 500.0