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Fair Value Measurements - Recurring Basis (Details) - Fair Value, Recurring - Level 2 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Assets and (Liabilities) at Fair Value
Liabilities at fair value	$ 4.0	$ 1.7
Interest rate contracts
Assets and (Liabilities) at Fair Value
Loss recorded to net finance costs	$ 2.0	$ (0.7)

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Fair value of financial and nonfinancial obligations.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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