Revenue Recognition (Performance obligation) (Details)
|
6 Months Ended |
Jun. 30, 2018 |
|---|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01 |
|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
|
| Expected timing of satisfaction |
12 months
|
| Percentage expected to be recognized |
44.00%
|
| Minimum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01 |
|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
|
| Expected timing of satisfaction |
3 years
|
| Maximum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01 |
|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
|
| Expected timing of satisfaction |
4 years
|