| **Net Property and Equipment (PPE by Class) (Details) - USD ($) $ in Thousands** | Dec. 31, 2016 | Dec. 31, 2015 |
|----------------------------------------------------------------------------------|---------------|---------------|
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | $ 2,614,875   | $ 2,384,530   |
| Less accumulated depreciation                                                    | 1,385,620     | 1,231,457     |
| Less accumulated amortization on property and equipment under capital leases     | 67,337        | 58,692        |
| Net property and equipment                                                       | 1,161,918     | 1,094,381     |
| Gross property and equipment under capital leases                                | 112,495       | 112,495       |
| Land and buildings                                                               |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 114,966       | 108,145       |
| Telephony transmission equipment and distribution facilities                     |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 1,271,425     | 1,215,796     |
| Cable transmission equipment and distribution facilities                         |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 231,539       | 218,259       |
| Studio equipment                                                                 |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 15,456        | 15,171        |
| Support equipment and systems                                                    |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 290,209       | 251,302       |
| Transportation equipment                                                         |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 23,674        | 17,398        |
| Customer premise equipment                                                       |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 158,513       | 155,971       |
| Fiber optic cable systems                                                        |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | 351,460       | 309,217       |
| Construction in Progress [Member]                                                |          |          |
| **Property, Plant and Equipment [Line Items]**                                   |          |          |
| Property and equipment                                                           | $ 157,633     | $ 93,271      |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land or leased assets).
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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.
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.
+ References
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| X                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                       |
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| X                                                                                                                                                               |
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| X                                                                                                                                                                         |
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| X                                                                                                                                                                         |
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| X                                                                                                                                                                             |
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| X                                                                                                                                                                      |
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