Property and equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property and equipment
Total property and equipment	$ 743,528		$ 743,528		$ 708,431
Less: accumulated depreciation and amortization	(350,588)		(350,588)		(328,188)
Total property and equipment, net	392,940		392,940		380,243
Depreciation and amortization expense
Total depreciation and amortization of property and equipment	19,529	$ 16,874	38,175	$ 35,883
Network access
Depreciation and amortization expense
Total depreciation and amortization of property and equipment	11,598	9,482	22,548	21,064
Network operations
Depreciation and amortization expense
Total depreciation and amortization of property and equipment	4,982	4,322	9,649	8,708
Development and technology
Depreciation and amortization expense
Total depreciation and amortization of property and equipment	2,724	2,808	5,457	5,587
General and administrative
Depreciation and amortization expense
Total depreciation and amortization of property and equipment	225	$ 262	521	$ 524
Leasehold improvements
Property and equipment
Total property and equipment	566,850		566,850		550,427
Construction in progress
Property and equipment
Total property and equipment	96,869		96,869		78,343
Software
Property and equipment
Total property and equipment	62,526		62,526		60,814
Computer equipment
Property and equipment
Total property and equipment	14,784		14,784		16,707
Furniture, fixtures and office equipment
Property and equipment
Total property and equipment	$ 2,499		$ 2,499		$ 2,140