Property and equipment: Exchange agreement (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property and equipment
Cash component of network equipment obtained in exchange transactions	$ 0.1	$ 0.1	$ 0.3	$ 0.8
Level 3
Property and equipment
Fair value of new equipment	$ 0.2	$ 0.3	$ 1.1	$ 2.6

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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