Summary of significant accounting policies (Details 3) - USD ($) $ in Thousands |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2015 |
Dec. 31, 2014 |
|
| Foreign Currency Translation | ||
| Cumulative foreign currency translation adjustments, net of tax in accumulated other comprehensive income | $ 783 | $ 443 |
| Income tax expense related to foreign currency translation adjustments | 0 | 0 |
| Recent accounting pronouncements | ||
| Short-term debt issuance cost classified as prepaid expenses and other current assets | 178 | 178 |
| Long-term debt issuance cost classified as other assets | $ 425 | $ 514 |
| DAS | Minimum | ||
| Revenue recognition | ||
| Term of the arrangement used to determine revenue recognition | 5 years | |
| DAS | Maximum | ||
| Revenue recognition | ||
| Term of the arrangement used to determine revenue recognition | 10 years | |
| Wholesale - Wi-Fi | Minimum | ||
| Revenue recognition | ||
| Term of the arrangement used to determine revenue recognition | 1 year | |
| Wholesale - Wi-Fi | Maximum | ||
| Revenue recognition | ||
| Term of the arrangement used to determine revenue recognition | 5 years |