Quarterly report pursuant to Section 13 or 15(d)

Revenue (Obligation) (Details)

v3.8.0.1
Revenue (Obligation) (Details)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
USD ($)
Revenue  
Total $ 523,739
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01  
Revenue  
Total $ 154,502
Remaining Performance Obligations  
Revenue recognition period 9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01  
Revenue  
Total $ 149,116
Remaining Performance Obligations  
Revenue recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01  
Revenue  
Total $ 84,152
Remaining Performance Obligations  
Revenue recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01  
Revenue  
Total $ 48,334
Remaining Performance Obligations  
Revenue recognition period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01  
Revenue  
Total $ 52,063
Remaining Performance Obligations  
Revenue recognition period 1 year