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Revenues (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Revenue from Contract with Customer [Abstract]          
Performance obligations satisfied or partially satisfied in previous periods $ 7.0 $ 8.7 $ 23.5 $ 12.9  
Contract asset 3.4   3.4   $ 2.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01          
Revenue from Contract with Customer [Abstract]          
Unfulfilled performance obligations $ 3.0   $ 3.0   $ 8.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]          
Performance obligation expected duration         24 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01          
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]          
Performance obligation expected duration 24 months   24 months