Interest Rate Hedge - Summary (Details) - Interest rate swaps - Hedging $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($) item	May 09, 2018 USD ($)
Interest Rate Hedge
Notional amount		$ 1,361.2
Number of interest rate swaps \| item	2
Fixed rate (as a percent)	2.70%
Reclassification of losses out of accumulated other comprehensive loss into earnings within next 12 months	$ 2.0
Term B Loans
Interest Rate Hedge
Fair value of debt	$ 2,257.2

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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Fixed interest rate related to the interest rate derivative.

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The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80845-113994

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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.

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