Description of Business and Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation — The Condensed Consolidated Financial Statements of the Company have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) and, in the opinion of management, include all adjustments necessary for a fair presentation of the results of operations, other comprehensive income, financial position, and cash flows for each period presented. The adjustments referred to above are of a normal and recurring nature. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to SEC rules and regulations for interim reporting. The Condensed Consolidated Balance Sheet as of December 31, 2012 was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. These Condensed Consolidated Financial Statements should be read in conjunction with the Company’s 2012 Annual Report on Form 10-K. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results expected for the full year or any other interim period.
Use of Estimates	Use of Estimates — Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported. Actual results could differ from those estimates. In the normal course of business, the Company is subject to various regulatory and tax proceedings, lawsuits, claims, and other matters. The Company believes adequate provision has been made for all such asserted and unasserted claims in accordance with U.S. GAAP. Such matters are subject to many uncertainties and outcomes that are not predictable with assurance.
Investment in CyrusOne	Investment in CyrusOne - We completed the IPO of CyrusOne on January 24, 2013, and as of that date, we no longer control its operations. As a result, effective January 24, 2013, our 69% ownership in CyrusOne is accounted for as an equity method investment. From that date, we recognize our proportionate share of CyrusOne's net income or loss as non-operating income or expense in our consolidated statement of operations. For the period January 1, 2013 through January 23, 2013, we consolidated CyrusOne's operating results. During the three and nine months ended September 30, 2013, the Company received cash dividends from CyrusOne totaling $7.2 million and $14.2 million, respectively. Dividends from CyrusOne are recognized as a reduction of our investment.
Property, Plant and Equipment	Property, Plant and Equipment — Property, plant and equipment is stated at original cost and presented net of accumulated depreciation and impairment losses. Depreciation expense is generally calculated using either the group depreciation method or the straight-line method. During the three months ended March 31, 2013, and in connection with ongoing reviews of the estimated remaining useful lives of property, plant and equipment, we shortened the estimated useful lives assigned to wireless network software to three years. This change resulted from smartphone-driven technology upgrades, enhancements and projected retirements. As a result of this change in estimate, we recorded depreciation expense of $8.5 million ($5.1 million net of tax) in the first quarter of 2013, which had the impact of increasing basic and diluted loss per share by approximately $0.03 per share.
Income Taxes	Income Taxes — The Company’s income tax provision for interim periods is determined through the use of an estimated annual effective tax rate applied to year-to-date ordinary income, as well as the tax effects associated with discrete items. For 2013, the Company expects its effective tax rate to be lower than statutory rates on its pre-tax loss. The Company's tax expense for the three months ended September 30, 2013 decreased from the prior year due to a reduction in the expected annual effective tax rate, which was driven by lower expected pre-tax income year-over-year. The Company's tax expense for the nine months ended September 30, 2013 decreased from the prior year primarily due to lower pre-tax income and a reduction in the annual effective tax rate. The tax impact of lower income was partially offset by a valuation allowance provision of $10.7 million for Texas margin credits, which effective with CyrusOne's IPO on January 24, 2013, are unlikely to be realized before their expiration date.
Operating Taxes	Operating Taxes — Certain operating taxes such as property, sales, use and gross receipts taxes are reported as expenses in operating income primarily within cost of services. These taxes are not included in income tax expense because the amounts to be paid are not dependent on our level of income. Liabilities for audit exposures are established based on management's assessment of the probability of payment. The provision for such liabilities is recognized as either property, plant and equipment, operating tax expense, or depreciation expense depending on the nature of the audit exposure. Upon resolution of an audit, any remaining liability not paid is released against the account in which it was originally recorded.
Recently Issued Accounting Standards	Recently Issued Accounting Standards — In February 2013, the Financial Accounting Standards Board ("FASB") amended the guidance in Accounting Standards Codification ("ASC") 220 on comprehensive income. The new guidance requires additional information to be disclosed about the amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amounts reclassified are required under U.S. generally accepted accounting principles to be reclassified in their entirety to net income. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income, cross references to other disclosures will be required. We adopted this new guidance beginning with our interim financial statements for the three months ended March 31, 2013. See Note 9 for our disclosures. In July 2013, the FASB issued new guidance under Accounting Standards Update 2013-11 regarding the presentation of unrecognized tax benefits in financial statements. This new standard requires the netting in the balance sheet of unrecognized tax benefits against a deferred tax asset for a same-jurisdiction loss or other carryforward that would apply in settlement of the uncertain tax positions. To the extent a net operating loss ("NOL") or tax credit carryforward is not available under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position, the unrecognized tax benefit would be presented in the balance sheet as a liability. This standard is effective for annual and interim periods beginning after December 15, 2013. We expect that the adoption of this standard will not have a material impact on our financial statements.
Earnings Per Share	Basic earnings per common share (“EPS”) is based upon the weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that would occur upon issuance of common shares for awards under stock-based compensation plans, exercise of warrants or conversion of preferred stock, but only to the extent that they are considered dilutive.
Fair Value Measurements	The fair value of our investment in CyrusOne was based on the closing market price of CyrusOne's common stock on September 30, 2013. This fair value measurement is considered Level 1 of the fair value hierarchy. The fair value of our long-term debt was based on closing or estimated market prices of the Company’s debt at September 30, 2013 and December 31, 2012, which is considered Level 2 of the fair value hierarchy. As of January 24, 2013, upon completion of the IPO of CyrusOne, we no longer consolidate CyrusOne. Therefore, the other financing arrangements related to CyrusOne are no longer accounted for in our consolidated financial statements. As of December 31, 2012, the fair value of other financing arrangements was calculated using a discounted cash flow model that incorporates current borrowing rates for obligations of similar duration, which is considered Level 3 of the fair value hierarchy.

Description of Business and Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2013

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation — The Condensed Consolidated Financial Statements of the Company have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) and, in the opinion of management, include all adjustments necessary for a fair presentation of the results of operations, other comprehensive income, financial position, and cash flows for each period presented.

The adjustments referred to above are of a normal and recurring nature. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to SEC rules and regulations for interim reporting.

The Condensed Consolidated Balance Sheet as of December 31, 2012 was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. These Condensed Consolidated Financial Statements should be read in conjunction with the Company’s 2012 Annual Report on Form 10-K. Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results expected for the full year or any other interim period.

Use of Estimates

Use of Estimates — Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported. Actual results could differ from those estimates. In the normal course of business, the Company is subject to various regulatory and tax proceedings, lawsuits, claims, and other matters. The Company believes adequate provision has been made for all such asserted and unasserted claims in accordance with U.S. GAAP. Such matters are subject to many uncertainties and outcomes that are not predictable with assurance.

Investment in CyrusOne

Investment in CyrusOne - We completed the IPO of CyrusOne on January 24, 2013, and as of that date, we no longer control its operations. As a result, effective January 24, 2013, our 69% ownership in CyrusOne is accounted for as an equity method investment. From that date, we recognize our proportionate share of CyrusOne's net income or loss as non-operating income or expense in our consolidated statement of operations. For the period January 1, 2013 through January 23, 2013, we consolidated CyrusOne's operating results. During the three and nine months ended September 30, 2013, the Company received cash dividends from CyrusOne totaling $7.2 million and $14.2 million, respectively. Dividends from CyrusOne are recognized as a reduction of our investment.

Property, Plant and Equipment

Property, Plant and Equipment — Property, plant and equipment is stated at original cost and presented net of accumulated depreciation and impairment losses. Depreciation expense is generally calculated using either the group depreciation method or the straight-line method. During the three months ended March 31, 2013, and in connection with ongoing reviews of the estimated remaining useful lives of property, plant and equipment, we shortened the estimated useful lives assigned to wireless network software to three years. This change resulted from smartphone-driven technology upgrades, enhancements and projected retirements. As a result of this change in estimate, we recorded depreciation expense of $8.5 million ($5.1 million net of tax) in the first quarter of 2013, which had the impact of increasing basic and diluted loss per share by approximately $0.03 per share.

Income Taxes

Income Taxes — The Company’s income tax provision for interim periods is determined through the use of an estimated annual effective tax rate applied to year-to-date ordinary income, as well as the tax effects associated with discrete items. For 2013, the Company expects its effective tax rate to be lower than statutory rates on its pre-tax loss. The Company's tax expense for the three months ended September 30, 2013 decreased from the prior year due to a reduction in the expected annual effective tax rate, which was driven by lower expected pre-tax income year-over-year. The Company's tax expense for the nine months ended September 30, 2013 decreased from the prior year primarily due to lower pre-tax income and a reduction in the annual effective tax rate. The tax impact of lower income was partially offset by a valuation allowance provision of $10.7 million for Texas margin credits, which effective with CyrusOne's IPO on January 24, 2013, are unlikely to be realized before their expiration date.

Operating Taxes

Operating Taxes — Certain operating taxes such as property, sales, use and gross receipts taxes are reported as expenses in operating income primarily within cost of services. These taxes are not included in income tax expense because the amounts to be paid are not dependent on our level of income. Liabilities for audit exposures are established based on management's assessment of the probability of payment. The provision for such liabilities is recognized as either property, plant and equipment, operating tax expense, or depreciation expense depending on the nature of the audit exposure. Upon resolution of an audit, any remaining liability not paid is released against the account in which it was originally recorded.

Recently Issued Accounting Standards

Recently Issued Accounting Standards — In February 2013, the Financial Accounting Standards Board ("FASB") amended the guidance in Accounting Standards Codification ("ASC") 220 on comprehensive income. The new guidance requires additional information to be disclosed about the amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amounts reclassified are required under U.S. generally accepted accounting principles to be reclassified in their entirety to net income. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income, cross references to other disclosures will be required. We adopted this new guidance beginning with our interim financial statements for the three months ended March 31, 2013. See Note 9 for our disclosures.

In July 2013, the FASB issued new guidance under Accounting Standards Update 2013-11 regarding the presentation of unrecognized tax benefits in financial statements. This new standard requires the netting in the balance sheet of unrecognized tax benefits against a deferred tax asset for a same-jurisdiction loss or other carryforward that would apply in settlement of the uncertain tax positions. To the extent a net operating loss ("NOL") or tax credit carryforward is not available under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position, the unrecognized tax benefit would be presented in the balance sheet as a liability. This standard is effective for annual and interim periods beginning after December 15, 2013. We expect that the adoption of this standard will not have a material impact on our financial statements.

Earnings Per Share

Basic earnings per common share (“EPS”) is based upon the weighted average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that would occur upon issuance of common shares for awards under stock-based compensation plans, exercise of warrants or conversion of preferred stock, but only to the extent that they are considered dilutive.

Fair Value Measurements

The fair value of our investment in CyrusOne was based on the closing market price of CyrusOne's common stock on September 30, 2013. This fair value measurement is considered Level 1 of the fair value hierarchy.

The fair value of our long-term debt was based on closing or estimated market prices of the Company’s debt at September 30, 2013 and December 31, 2012, which is considered Level 2 of the fair value hierarchy.

As of January 24, 2013, upon completion of the IPO of CyrusOne, we no longer consolidate CyrusOne. Therefore, the other financing arrangements related to CyrusOne are no longer accounted for in our consolidated financial statements. As of December 31, 2012, the fair value of other financing arrangements was calculated using a discounted cash flow model that incorporates current borrowing rates for obligations of similar duration, which is considered Level 3 of the fair value hierarchy.