Fair Value Measurements - Effect of Interest Rate Swap Contracts Designated as Cash Flow Hedges (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Total amounts of expense line item presented in the statements of operations and comprehensive loss in which the effects of cash flow hedges are recorded	$ (597.2)	$ (609.7)	$ (661.4)
Hedged item	(16.6)
Derivative designated as hedging instrument	$ 14.0

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration