Property and equipment (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Depreciation, Depletion and Amortization
Total depreciation and amortization of property and equipment	$ 8,054	$ 5,784
Network access
Depreciation, Depletion and Amortization
Total depreciation and amortization of property and equipment	4,832	3,862
Network operations
Depreciation, Depletion and Amortization
Total depreciation and amortization of property and equipment	1,986	1,187
Development and Technology Expense
Depreciation, Depletion and Amortization
Total depreciation and amortization of property and equipment	1,174	697
General and administrative
Depreciation, Depletion and Amortization
Total depreciation and amortization of property and equipment	$ 62	$ 38