Schedule III - Real Estate Investments and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 6,256,248	$ 6,093,541
Accumulated Depreciation	(4,054,748)	$ (3,720,890)
Land
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	26,833
Accumulated Depreciation	(201)
Building and Improvements
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	318,616
Accumulated Depreciation	$ (148,432)
Building and Improvements | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	3 years
Building and Improvements | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	40 years
Poles
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 234,393
Accumulated Depreciation	$ (173,441)
Poles | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	13 years
Poles | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	40 years
Fiber
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 2,024,564
Accumulated Depreciation	$ (820,389)
Fiber | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	7 years
Fiber | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	40 years
Copper
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 3,538,565
Accumulated Depreciation	$ (2,856,327)
Copper | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	7 years
Copper | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	40 years
Conduit
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 89,661
Accumulated Depreciation	$ (54,487)
Conduit | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	13 years
Conduit | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	47 years
Towers
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 4,307
Accumulated Depreciation	$ (659)
Towers | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	20 years
Towers | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	49 years
Real Property Interests
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 12,265
Accumulated Depreciation	$ (94)
Real Property Interests | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	50 years
Real Property Interests | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	99 years
Other assets
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 5,299
Accumulated Depreciation	$ (718)
Other assets | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	15 years
Other assets | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Depreciable Lives	20 years
Construction in progress
Real Estate And Accumulated Depreciation [Line Items]
Gross Amount Carried at Close of Period	$ 1,745