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Asset Retirement Obligation - Schedule of Change in Asset Retirement Obligation (Details)
$ in Millions
6 Months Ended
Jun. 30, 2019
USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]  
As of December 31, 2018 $ 34.2
Accretion expense 1.3
Additions 0.2
Liabilities settled (1.1)
Foreign currency translation adjustments 0.2
As of June 30, 2019 $ 34.8