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Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of operating segments | segment	3
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Net decrease to total equity	$ (1,096.1)	$ (1,128.7)		$ (1,208.3)	$ (651.1)
Impact of adoption of new accounting standards
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net decrease to total equity		$ 4.1			$ 1.4
Impact of adoption of new accounting standards | ASU 2016-13
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net decrease to total equity			$ 4.1
GLP
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Ownership interest percentage in subsidiaries	70.00%

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