Goodwill and intangible assets - Intangible assets rollforward (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Changes in intangible assets | ||
| Balance at beginning of year | $ 14,940 | $ 19,152 |
| Measurement period adjustments for acquisition of Elauwit | (48) | |
| Reclassification of assets held for sale, net | 407 | |
| Amortization expense | (4,288) | (4,571) |
| Balance at end of year | $ 10,652 | $ 14,940 |