Property, Plant and Equipment - Schedule of Carrying Value of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 9,031,972	$ 8,776,840
Less accumulated depreciation	(5,631,217)	(5,503,487)
Net property, plant and equipment	3,400,755	3,273,353
Land
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	27,936	27,945
Building and Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 358,570	351,305
Building and Improvements | Minimum
Property Plant And Equipment [Line Items]
Depreciable Lives	3 years
Building and Improvements | Maximum
Property Plant And Equipment [Line Items]
Depreciable Lives	40 years
Poles
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 273,934	266,758
Fiber
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 3,875,028	3,737,372
Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 314,256	298,912
Equipment | Minimum
Property Plant And Equipment [Line Items]
Depreciable Lives	5 years
Equipment | Maximum
Property Plant And Equipment [Line Items]
Depreciable Lives	7 years
Copper
Property Plant And Equipment [Line Items]
Depreciable Lives	20 years
Property, plant and equipment, gross	$ 3,902,265	3,850,987
Conduit
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 89,960	89,773
Tower assets
Property Plant And Equipment [Line Items]
Depreciable Lives	20 years
Property, plant and equipment, gross	$ 8,544	8,571
Finance Lease Assets
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	71,444	74,103
Other assets
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 10,644	10,553
Other assets | Minimum
Property Plant And Equipment [Line Items]
Depreciable Lives	15 years
Other assets | Maximum
Property Plant And Equipment [Line Items]
Depreciable Lives	20 years
Corporate assets
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 13,829	13,475
Corporate assets | Minimum
Property Plant And Equipment [Line Items]
Depreciable Lives	3 years
Corporate assets | Maximum
Property Plant And Equipment [Line Items]
Depreciable Lives	7 years
Construction in progress
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 85,562	$ 47,086