Quarterly report pursuant to Section 13 or 15(d)

Revenue (Obligation) (Details)

v3.10.0.1
Revenue (Obligation) (Details)
$ in Thousands
 9 Months Ended
Sep. 30, 2018
USD ($)
Revenue from Contract with Customer [Abstract]  
Total $ 481,213
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01  
Revenue from Contract with Customer [Abstract]  
Total $ 52,301
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01  
Remaining Performance Obligations  
Revenue recognition period 3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01  
Revenue from Contract with Customer [Abstract]  
Total $ 168,264
Remaining Performance Obligations  
Revenue recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01  
Revenue from Contract with Customer [Abstract]  
Total $ 101,449
Remaining Performance Obligations  
Revenue recognition period 2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01  
Revenue from Contract with Customer [Abstract]  
Total $ 58,544
Remaining Performance Obligations  
Revenue recognition period 3 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01  
Revenue from Contract with Customer [Abstract]  
Total $ 44,319
Remaining Performance Obligations  
Revenue recognition period 4 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01  
Revenue from Contract with Customer [Abstract]  
Total $ 56,336
Remaining Performance Obligations  
Revenue recognition period