Financial Instruments and Fair Value Measurements - Derivative Financial Instruments (Details) - Designated as hedging instrument - Cash flow hedge - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amount	$ 673.4	$ 507.2
Fair Value - asset (liability)	(26.3)	(4.0)
Interest rate swap, maturity Sep 2021
Derivative [Line Items]
Notional Amount	$ 7.0	7.2
Strike (percent)	6.03%
Fair Value - asset (liability)	$ (0.2)	(0.2)
Interest rate swap, maturity Jun 2020
Derivative [Line Items]
Notional Amount	$ 250.0	250.0
Strike (percent)	1.72%
Fair Value - asset (liability)	$ (0.1)	3.0
Interest rate swap, maturity Mar 2024
Derivative [Line Items]
Notional Amount	$ 250.0	250.0
Strike (percent)	3.04%
Fair Value - asset (liability)	$ (14.7)	(6.8)
Cross-currency swap, maturity May 2034 1
Derivative [Line Items]
Notional Amount	41.6	0.0
Fair Value - asset (liability)	$ (2.6)	0.0
Cross-currency swap, maturity May 2034 1 \| GBP \| Minimum
Derivative [Line Items]
Strike (percent)	4.82%
Cross-currency swap, maturity May 2034 1 \| GBP \| Maximum
Derivative [Line Items]
Strike (percent)	10.96%
Cross-currency swap, maturity May 2034 1 \| USD
Derivative [Line Items]
Strike (percent)	9.80%
Cross-currency swap, maturity May 2034 2
Derivative [Line Items]
Notional Amount	$ 41.6	0.0
Fair Value - asset (liability)	$ (2.6)	0.0
Cross-currency swap, maturity May 2034 2 \| GBP \| Minimum
Derivative [Line Items]
Strike (percent)	4.82%
Cross-currency swap, maturity May 2034 2 \| GBP \| Maximum
Derivative [Line Items]
Strike (percent)	10.96%
Cross-currency swap, maturity May 2034 2 \| USD
Derivative [Line Items]
Strike (percent)	9.803%
Cross-currency swap, maturity May 2034 3
Derivative [Line Items]
Notional Amount	$ 41.6	0.0
Fair Value - asset (liability)	$ (2.9)	0.0
Cross-currency swap, maturity May 2034 3 \| GBP \| Minimum
Derivative [Line Items]
Strike (percent)	4.82%
Cross-currency swap, maturity May 2034 3 \| GBP \| Maximum
Derivative [Line Items]
Strike (percent)	10.96%
Cross-currency swap, maturity May 2034 3 \| USD
Derivative [Line Items]
Strike (percent)	9.745%
Cross-currency swap, maturity May 2034 4
Derivative [Line Items]
Notional Amount	$ 41.6	0.0
Fair Value - asset (liability)	$ (3.2)	$ 0.0
Cross-currency swap, maturity May 2034 4 \| GBP \| Minimum
Derivative [Line Items]
Strike (percent)	4.82%
Cross-currency swap, maturity May 2034 4 \| GBP \| Maximum
Derivative [Line Items]
Strike (percent)	10.96%
Cross-currency swap, maturity May 2034 4 \| USD
Derivative [Line Items]
Strike (percent)	9.755%

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
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-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

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