Property and equipment- Depreciation and amortization (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Depreciation and amortization
Total depreciation and amortization of property and equipment	$ 13,093	$ 10,033	$ 34,801	$ 27,899
Network access
Depreciation and amortization
Total depreciation and amortization of property and equipment	7,227	6,277	18,689	17,264
Network operations
Depreciation and amortization
Total depreciation and amortization of property and equipment	3,733	2,087	10,183	5,916
Development and technology
Depreciation and amortization
Total depreciation and amortization of property and equipment	1,881	1,377	5,172	3,887
General and administrative
Depreciation and amortization
Total depreciation and amortization of property and equipment	$ 252	$ 292	$ 757	$ 832