v3.6.0.2
Summary of significant accounting policies - Revenue recognition (Details)
12 Months Ended
Dec. 31, 2016
DAS license agreements | Minimum  
Revenue recognition  
Term of the arrangement used to determine revenue recognition 5 years
DAS license agreements | Maximum  
Revenue recognition  
Term of the arrangement used to determine revenue recognition 20 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