Summary of significant accounting policies - Principles of consolidation (Details) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Jan. 01, 2016 |
|---|---|---|
| Accounting Standards Update 2016-09 [Member] | Early adoption | ||
| Basis of presentation | ||
| Increase to additional paid-in capital and accumulated deficit due to cumulative effect of a change in accounting principle | $ 94 | |
| Accounting Standards Update 2016-09 [Member] | Early adoption | Federal | ||
| Basis of presentation | ||
| Increase to deferred tax assets | 6,933 | |
| Accounting Standards Update 2016-09 [Member] | Early adoption | State | ||
| Basis of presentation | ||
| Increase to deferred tax assets | $ 589 | |
| Chicago Concourse Development Group, LLC | ||
| Principles of consolidation | ||
| Percentage of ownership in subsidiaries | 70.00% | |
| Boingo Holding Participacoes Ltda. | ||
| Principles of consolidation | ||
| Percentage of ownership in subsidiaries | 75.00% |