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Financial Instruments - Schedule of Financial Instruments (Details) - USD ($) $ in Millions | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Derivative [Line Items] |  |  |
Interest rate cap, fair value | $ 23.5 |  | $ 5.4
Cap agreement effective 1/17/17-12/31/18 |  |  |
Derivative [Line Items] |  |  |
Notional amount | 1,400.0 |  |
Interest rate cap, fair value | 6.4 |  | 5.4
Cap agreement effective 12/31/18-12/31/20 |  |  |
Derivative [Line Items] |  |  |
Notional amount | 1,400.0 | $ 1,400.0 |
Interest rate cap, fair value | $ 17.1 |  | $ 0.0

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References 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 + Details
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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other 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 after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 + Details
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