Property, Plant and Equipment - Schedule of Carrying Value of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 8,295,035	$ 8,123,305
Less accumulated depreciation	(5,093,599)	(4,914,299)
Net property, plant and equipment	3,201,436	3,209,006
Land
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	27,567	29,304
Building and Improvements
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 345,754	340,238
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
Real Property Interests
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 4,630	34,878
Poles
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 255,103	248,989
Fiber
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 3,158,337	3,005,304
Equipment
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 266,933	256,838
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	$ 3,756,758	3,721,649
Conduit
Property Plant And Equipment [Line Items]
Depreciable Lives	30 years
Property, plant and equipment, gross	$ 89,768	89,692
Tower assets
Property Plant And Equipment [Line Items]
Depreciable Lives	20 years
Property, plant and equipment, gross	$ 127,577	120,073
Capital Lease Assets
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	128,530	123,017
Other assets
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 11,798	11,524
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	$ 4,733	4,214
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	$ 117,547	$ 137,585