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Segment information (Details) $ in Thousands	3 Months Ended		6 Months Ended
Segment information (Details) $ in Thousands	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Geographic information
Number of operating segments \| segment			1
Revenues	$ 148,450	$ 147,879	$ 297,622	$ 294,656
Long-lived assets, net	461,390		461,390		$ 457,892
On-net
Geographic information
Revenues	111,975	111,041	224,609	220,989
Off-net
Geographic information
Revenues	36,282	36,699	72,668	73,422
Non-core
Geographic information
Revenues	193	139	345	245
North America
Geographic information
Revenues	118,698	117,140	236,988	233,537
Long-lived assets, net	341,912		341,912		331,537
North America \| On-net
Geographic information
Revenues	86,686	85,123	173,128	169,589
North America \| Off-net
Geographic information
Revenues	31,839	31,892	63,548	63,735
North America \| Non-core
Geographic information
Revenues	173	125	312	213
Europe and other
Geographic information
Long-lived assets, net	119,478		119,478		$ 126,355
Europe
Geographic information
Revenues	24,524	26,880	50,303	53,910
Europe \| On-net
Geographic information
Revenues	20,458	22,372	41,954	44,792
Europe \| Off-net
Geographic information
Revenues	4,046	4,494	8,320	9,086
Europe \| Non-core
Geographic information
Revenues	20	14	29	32
Latin America
Geographic information
Revenues	1,387	1,054	2,838	1,882
Latin America \| On-net
Geographic information
Revenues	1,330	1,005	2,722	1,817
Latin America \| Off-net
Geographic information
Revenues	57	49	115	65
Latin America \| Non-core
Geographic information
Revenues			1
Asia Pacific
Geographic information
Revenues	3,641	2,712	7,122	5,156
Asia Pacific \| On-net
Geographic information
Revenues	3,321	2,449	6,462	4,622
Asia Pacific \| Off-net
Geographic information
Revenues	320	263	657	534
Asia Pacific \| Non-core
Geographic information
Revenues			3
Africa
Geographic information
Revenues	200	93	371	171
Africa \| On-net
Geographic information
Revenues	180	92	343	169
Africa \| Off-net
Geographic information
Revenues	$ 20	$ 1	$ 28	$ 2