Revenue Recognition - Contract Terms (Details) |
3 Months Ended |
|---|---|
Mar. 31, 2018 | |
| Services | Minimum | |
| Contract terms | |
| Contract term, high end of range | 10 years |
| Services | Maximum | |
| Contract terms | |
| Contract term, low end of range | 1 year |
| Term License Software | |
| Contract terms | |
| Committed contract term | 1 month |