| **Variable Interest Entities**                      | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                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| **Variable Interest Entity Disclosures [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        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| Variable Interest Entities                          | Variable Interest EntitiesNew Markets Tax Credit EntitiesWe have entered into several arrangements under the NMTC program with US Bancorp to help fund a project that extended terrestrial broadband service for the first time to rural Northwestern Alaska communities via a high capacity hybrid fiber optic and microwave network (“TERRA-NW”).  The NMTC program was provided for in the Community Renewal Tax Relief Act of 2000 (the “Act”) to induce capital investment in qualified lower income communities.  The Act permits taxpayers to claim credits against their federal income taxes for up to 39% of qualified investments in the equity of community development entities (“CDEs”).  CDEs are privately managed investment institutions that are certified to make qualified low-income community investments.On August 30, 2011, we entered into the first arrangement (“NMTC #1”).  In connection with the NMTC #1 transaction we loaned $58.3 million to TIF, a special purpose entity created to effect the financing arrangement, at 1% interest due August 30, 2041.  Simultaneously, US Bancorp invested $22.4 million in TIF.  TIF then contributed US Bancorp’s contribution and the loan proceeds to certain CDEs.  The CDEs, in turn, loaned the $76.8 million in funds less payment of placement fees, at interest rates varying from 1% to 3.96%, to Unicom, as partial financing for TERRA-NW.On October 3, 2012, we entered into the second arrangement (“NMTC #2”).  In connection with the NMTC #2 transaction we loaned $37.7 million to TIF 2 and TIF 2-USB, special purpose entities created to effect the financing arrangement, at 1% interest due October 2, 2042.  Simultaneously, US Bancorp invested $17.5 million in TIF 2 and TIF 2-USB.  TIF 2 and TIF 2-USB then contributed US Bancorp’s contributions and the loan proceeds to certain CDEs.  The CDEs, in turn, loaned the $55.2 million in funds less payment of placement fees, at interest rates varying from 0.7099% to 0.7693%, to Unicom, as partial financing for TERRA-NW.On December 11, 2012, we entered into the third arrangement (“NMTC #3”).  In connection with the NMTC #3 transaction we loaned $8.2 million to TIF 3, a special purpose entity created to effect the financing arrangement, at 1% interest due December 10, 2042.  Simultaneously, US Bancorp invested $3.8 million in TIF 3.  TIF 3 then contributed US Bancorp’s contributions and the loan proceeds to a CDE.  The CDE, in turn, loaned the $12.0 million in funds less payment of placement fees, at an interest rate of 1.35%, to Unicom, as partial financing for TERRA-NW.US Bancorp is the sole investor in TIF, TIF 2, TIF 2-USB and TIF 3, and as such, is entitled to substantially all of the benefits derived from the NMTCs.  All of the loan proceeds to Unicom net of syndication and arrangement fees, were restricted for use on TERRA-NW.  We completed construction of TERRA-NW and placed the final phase into service in 2014.These transactions include put/call provisions whereby we may be obligated or entitled to repurchase US Bancorp’s interests in TIF, TIF 2, TIF 2-USB and/or TIF 3. We believe that US Bancorp will exercise the put options in August 2018, October 2019 and December 2019, at the end of the compliance periods for NMTC #1, NMTC #2 and NMTC #3, respectively.  The NMTCs are subject to 100% recapture for a period of seven years as provided in the Internal Revenue Code.  We are required to be in compliance with various regulations and contractual provisions that apply to the NMTC arrangements.  Non-compliance with applicable requirements could result in projected tax benefits not being realized by US Bancorp.  We have agreed to indemnify US Bancorp for any loss or recapture of NMTCs until such time as our obligation to deliver tax benefits is relieved.  There have been no credit recaptures as of September 30, 2016.  The value attributed to the puts/calls is nominal.We have determined that TIF, TIF 2, TIF 2-USB and TIF 3 are VIEs.  The consolidated financial statement of TIF, TIF 2, TIF 2-USB and TIF 3 include the CDEs discussed above.  The ongoing activities of the VIEs – collecting and remitting interest and fees and NMTC compliance – were all considered in the initial design and are not expected to significantly affect economic performance throughout the life of the VIEs.  Management considered the contractual arrangements that obligate us to deliver tax benefits and provide various other guarantees to US Bancorp; US Bancorp’s lack of a material interest in the underlying economics of the project; and the fact that we are obligated to absorb losses of the VIEs.  We concluded that we are the primary beneficiary of each and consolidated the VIEs in accordance with the accounting standard for consolidation.US Bancorp’s contributions, net of syndication fees and other direct costs incurred in structuring the NMTC arrangements, are included in Non-controlling Interests on the Consolidated Balance Sheets.  Incremental costs to maintain the structure during the compliance period are recognized as incurred to selling, general and administrative expense.The assets and liabilities of our consolidated VIEs were $140.9 million and $104.2 million, respectively, as of September 30, 2016 and December 31, 2015.Equity Method InvestmentWe own a 40.8% interest in a next generation carrier-class communications services firm. We account for our investment using the equity method.  Due to declining economic conditions in the sector in which it operates, additional financing was needed for the company to maintain its business plan.  In March 2015, the existing owners provided financial support in the form of a loan of which our portion was $3.0 million. We determined that the additional financing provided to the company was a reconsideration event under ASC 810 and subsequently determined that the entity is a VIE due to insufficient equity to finance its operations as a result of the decline in economic conditions.  We concluded that the company's board has the power to direct the significant activities of the entity. The board is comprised of five members of which we may choose two of the board members. As we do not control the board, we concluded that we do not have the power to direct the significant activities of the entity and are not the primary beneficiary. During the second quarter of 2015, it became apparent that we would not recover the carrying value of our investment and we subsequently wrote-off the entire value of our investment. We received full payment on the $3.0 million note receivable in January 2016 and we do not have a contractual obligation to provide additional financing. We currently have no exposure to loss related to our involvement with the VIE. |

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| - Definition
Variable Interest Entity Disclosures [Abstract]
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No definition available.
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| - Definition
The entire disclosure for a variable interest entity (VIE), including but not limited to, judgments and assumptions in determining whether to consolidate and in identifying the primary beneficiary, gain (loss) recognized on the initial consolidation of the VIE, terms of arrangements, amounts and classification of the VIE's assets and liabilities, and the entity's maximum exposure to loss.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -URI http://asc.fasb.org/extlink&oid=64801991&loc=SL6759159-111685Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=64801991&loc=d3e5728-111685Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64801991&loc=d3e5710-111685
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