Quarterly report pursuant to Section 13 or 15(d)

Revenue (Remaining Performance Obligations) (Details)

v3.8.0.1
Revenue (Remaining Performance Obligations) (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2018
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 151.5
Revenue, remaining performance obligation, period 9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 195.2
Revenue, remaining performance obligation, period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 172.1
Revenue, remaining performance obligation, period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 93.7
Revenue, remaining performance obligation, period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Revenue, remaining performance obligation $ 63.9
Revenue, remaining performance obligation, period 1 year