Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Gross amount of debt extinguished.

+ References

No definition available.

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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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.

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Debt and Other Financing Arrangements - Corporate Credit Agreement (2012 through 2017) (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 02, 2017	Sep. 30, 2013
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity								$ 200.0
Loss (Gain) on Extinguishment of Debt	$ 1.3				$ 1.3	$ 3.2	$ 19.0
Tranche B Term Loan due 2020 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Face Amount								315.8	$ 540.0
Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity								30.0
Bridge Loan [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity								$ 25.0
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 150.0				150.0
Revolving Credit Facility And Tranche B Term Loan due 2020 [Member]
Line of Credit Facility [Line Items]
Loss (Gain) on Extinguishment of Debt		$ 3.2
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Loss (Gain) on Extinguishment of Debt				$ 1.7
Tranche B Term Loan [Member]
Line of Credit Facility [Line Items]
Loss (Gain) on Extinguishment of Debt		$ 2.6
Tranche B Term Loan due 2020 [Member]
Line of Credit Facility [Line Items]
Loss (Gain) on Extinguishment of Debt			2.2
Extinguishment of Debt, Amount			$ 208.0
Senior Notes due 2020 [Member]
Line of Credit Facility [Line Items]
Loss (Gain) on Extinguishment of Debt							17.8
Extinguishment of Debt, Amount							$ 478.5
London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					3.25%			3.75%
Debt Instrument, Basis Spread on Variable Rate					1.00%		1.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.00%		1.00%		3.00%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.50%				3.50%
Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate							0.50%
Base Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					2.25%			2.75%
Base Rate [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.00%				2.00%
Base Rate [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.50%				2.50%