| **Subsequent Events**            | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                             |
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| **Subsequent Events [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                       |
| Subsequent Events [Text Block]   | Subsequent EventOn April 29, 2016, we signed a definitive agreement to sell the majority of our urban wireless rooftop and tower sites to Vertical Bridge for approximately $90.0 million.  We will lease the sites from Vertical Bridge following the close of the transaction.  We expect the transaction to close in mid-2016.  The closing is subject to customary closing conditions. |

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| - Definition
The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.
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