Summary of significant accounting policies - Revenue recognition - Terms of contracts (Details) |
6 Months Ended |
|---|---|
|
Jun. 30, 2019
item
| |
| Minimum | |
| Revenue recognition | |
| Payment terms | 30 days |
| Maximum | |
| Revenue recognition | |
| Payment terms | 60 days |
| Military and retail | |
| Revenue recognition | |
| Cancellation period of renewal option prior end of current contract period | 5 days |
| Multifamily | |
| Revenue recognition | |
| Number of performance obligations | 2 |
| Multifamily | Minimum | |
| Revenue recognition | |
| Initial term of the arrangement | 3 years |
| Multifamily | Maximum | |
| Revenue recognition | |
| Initial term of the arrangement | 5 years |
| DAS license agreements | Minimum | |
| Revenue recognition | |
| Initial term of the arrangement | 5 years |
| DAS license agreements | Maximum | |
| Revenue recognition | |
| Initial term of the arrangement | 20 years |
| Wholesale-Wi-Fi | Minimum | |
| Revenue recognition | |
| Initial term of the arrangement | 1 year |
| Wholesale-Wi-Fi | Maximum | |
| Revenue recognition | |
| Initial term of the arrangement | 3 years |