Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Use of Estimates	Use of Estimates—The preparation of financial statements, in accordance with GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and disclosure of contingent assets and liabilities. The estimates and assumptions used in the accompanying financial statements are based upon management’s evaluation of the relevant facts and circumstances as of the date of the financial statements. Actual results may differ from the estimates and assumptions used in preparing the accompanying financial statements, and such differences could be material.
Property, Plant and Equipment	Property, Plant and Equipment—Property, plant and equipment is stated at original cost, net of accumulated depreciation. The Company capitalizes costs incurred in bringing property, plant and equipment to an operational state, including all activities directly associated with the acquisition, construction, and installation of the related assets it owns. The Company also enters into leasing arrangements providing for the long‑term use of constructed fiber that is then integrated into the Company’s network infrastructure. For each lease that qualifies as a capital lease, the present value of the lease payments, which may include both periodic lease payments over the term of the lease as well as upfront payments to the lessor, is capitalized at the inception of the lease and included in property and equipment. Certain Distribution System property, plant and equipment are depreciated using a group composite depreciation method. Under this method, when property is retired, the original cost, net of salvage value, is charged against accumulated depreciation and no immediate gain or loss is recognized on the disposition of the property. For all other property, which includes amortization of capital lease assets, depreciation is computed using the straight-line method over the estimated useful life of the respective property. When the property is retired or otherwise disposed of, the related cost and accumulated depreciation are written-off, with the corresponding gain or loss reflected in operating results. Construction in progress includes direct materials and labor related to fixed assets during the construction period. Depreciation will begin once the construction period has ceased and the related asset has been placed into service, in which it will be depreciated over its useful life. Costs of maintenance and repairs to property, plant and equipment subject to the Master Lease are the responsibility of our tenant. Costs of maintenance and repairs to property, plant and equipment not subject to triple-net leasing arrangements are expensed as incurred. We acquire real property interests from third parties who own land where communications infrastructure assets are located and desire to monetize the underlying real property. These real property interests entitle us to receive rental payments from leases on our sites. The financial results of the acquired real property interests are included in the Leasing segment from the date of acquisition and were not material, individually or in the aggregate, to our results of operations. Real property interests are recorded in property, plant and equipment on our Consolidated Balance Sheet.
Tenant Capital Improvements	Tenant Capital Improvements—Our lease with Windstream provides that tenant funded capital improvements (“TCI’s”), defined as maintenance, repair, overbuild, upgrade or replacements to the leased network, including, without limitation, the replacement of copper distribution systems with fiber distribution systems, automatically become property of CS&L upon their construction by Windstream. We receive non-monetary consideration related to the TCIs as they automatically become our property, and we recognize the cost basis of TCIs that are capital in nature as real estate investments and deferred revenue. We depreciate the real estate investments over their estimated useful lives and amortize the deferred revenue as additional leasing revenues over the same depreciable life of the TCI assets. At December 31, 2016 and December 31, 2015, the net book value of TCI’s recorded as a component of property, plant and equipment on our Consolidated Balance Sheet was $218.7 million and $67.8 million, respectively. For the year ended December 31, 2016 we recognized $6.1 million of revenue and depreciation expense related to TCIs. From the period April 24, 2015 to December 31, 2015 we recognized $0.8 million of revenue and depreciation expense related to TCIs.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets—We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset group may not be recoverable from future undiscounted net cash flows we expect the asset group to generate. If the asset group is not fully recoverable, an impairment loss would be recognized for the difference between the carrying value of the asset group and its estimated fair value based on discounted net future cash flows. During the year ended December 31, 2016 and from the period April 24, 2015 to December 31, 2015 no impairment losses were recognized.
Asset Retirement Obligations	Asset Retirement Obligations—The Company records obligations to perform asset retirement activities, primarily including requirements to remove equipment from leased space or customer sites as required under the terms of the related lease and customer agreements. The fair value of the liability for asset retirement obligations, which represents the net present value of the estimated expected future cash outlay, is recognized in the period in which it is incurred and the fair value of the liability can reasonably be estimated. The liability accretes as a result of the passage of time and related accretion expense is recognized in the consolidated statement of operations. The associated asset retirement costs are capitalized as an additional carrying amount of the related long‑lived asset and depreciated on a straight-line basis over the asset’s useful life.
Cash and Cash Equivalents	Cash and Cash Equivalents—Cash and cash equivalents include all non-restricted cash held at financial institutions and other non-restricted highly liquid short-term investments with original maturities of three months or less.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities—We account for our derivatives in accordance with FASB ASC 815, Derivatives and Hedging, in which we reflect all derivative instruments at fair value as either assets or liabilities on our Consolidated Balance Sheet. For derivative instruments that are designated and qualify as hedging instruments, we record the effective portion of the gain or loss on the hedged instruments as a component of accumulated other comprehensive income or loss. Any ineffective portion of a derivative’s change in fair value is immediately recognized within net income. For derivatives that do not meet the criteria for hedge accounting, changes in fair value are immediately recognized within net income. See Note 5 and Note 7.
Customer List Intangible Assets	Customer List Intangible Assets—Customer list intangible assets are presented in the financial statements at cost less accumulated amortization and are amortized using the sum-of-the-digits method over their estimated useful lives.
Foreign Currency Translation	Foreign Currency Translation—The financial statements of our international subsidiaries whose functional currency is the local currency are translated into U.S. dollars using the exchange rate at the balance sheet date for assets and liabilities and the weighted average exchange rate for the applicable period for revenues, expenses, gains and losses. Translation adjustments are recorded as a separate component of comprehensive income in stockholders’ equity.
Reclassifications	Reclassifications—Certain prior year amounts have been reclassified to conform with current year presentation.
Transaction Related Costs	Transaction Related Costs—The Company expenses transaction related costs in the period in which they are incurred and services are received. Transaction related costs include incremental acquisition pursuit, transaction and integration costs, including unsuccessful acquisition pursuit costs. Pursuit and transaction costs include professional services (legal, accounting, advisory, regulatory, etc.), finder’s fees, travel expenses, and other direct expenses associated with an acquisition. Integration costs include direct costs necessary to integrate an acquired business, including professional services, systems and data conversion, severance and retention bonuses payable to employees of an acquired business.
Debt Issuance Costs	Debt Issuance Costs—The Company recognizes debt issuance costs related to a recognized debt liability as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts. The costs, which include underwriting, legal, and other direct costs related to the issuance of debt, are amortized over the contractual term of the debt using the effective interest method.
Revenue Recognition	Revenue Recognition—We recognize leasing revenues on a straight-line basis over the applicable lease term when collectability is reasonably assured. Recognizing leasing income on a straight-line basis generally results in recognized revenues during the first half of the lease term in excess of cash amounts contractually due from our tenants, creating a straight-line rent receivable. We evaluate the collectability of straight-line rent receivables and record a provision for doubtful accounts if management believes the receivables to be uncollectible. At December 31, 2016 and December 31, 2015, no allowance was recorded related to our straight-line rent receivable. We lease the Distribution Systems to Windstream under a triple-net lease basis, whereby Windstream is responsible for the costs related to operating the Distribution Systems, including property taxes, insurance and maintenance and repair costs. As a result, we do not record an obligation related to the payment of property taxes, as Windstream makes direct payments to the taxing authorities. Consumer CLEC Business revenues are primarily derived from providing access to or usage of leased networks and facilities, and are recognized over the period that the corresponding services are rendered to customers. Revenues derived from other telecommunications services, including broadband, long distance and enhanced service revenues are recognized monthly as services are provided. Sales of customer premise equipment and modems are recognized when products are delivered to and accepted by customers. The Company recognizes service revenues related to its broadband transport and backhaul communications services when (i) persuasive evidence of an arrangement exists, (ii) the services have been provided to the customer, (iii) the sales price is fixed or determinable, and (iv) the collection of the sales price is reasonably assured. Services provided to the Company’s customers are rendered pursuant to contractual fee‑based arrangements, which generally provide for recurring fees charged for the use of designated portions of the Company’s network and typically range for a period of three to ten years. The Company’s revenue arrangements often include upfront fees charged to the customer for the cost of establishing the necessary components of the Company’s network prior to the commencement of use by the customer. Fees charged to customers for the recurring use of the Company’s network are recognized during the related periods of service. Upfront fees that are billed in advance of providing services are deferred until such time the customer accepts the Company’s network and then are recognized as service revenues ratably over a period in which substantive services required under the revenue arrangement are expected to be performed, which is the initial term of the arrangement. We evaluate the collectability of service receivables by considering a variety of factors. The Company typically does not require collateral. When the Company becomes aware of a specific customer’s inability to meet its financial obligations, the Company records a specific reserve for bad debt to reduce the related accounts receivable to the amount the Company reasonably believes is collectible. When appropriate, the Company also records reserves for bad debts for all other customers based on a variety of factors including the length of time the receivable is past due, the financial health of the customer, macroeconomic considerations, and historical experience. If circumstances related to specific customers change, the Company adjusts its estimates of the recoverability of receivables as needed. At December 31, 2016 the allowance recorded for service receivables was $1.4 million. At December 31, 2015 no allowance was recorded for service receivables.
Stock-Based Compensation	Stock-Based Compensation—We account for stock-based compensation using the fair value method of accounting. We have determined that our stock-based payment awards granted in exchange for employee services qualify as equity classified awards, which are measured based on the fair value of the award on the date of the grant. The fair value of restricted stock-based payments is based on the market value of our common stock on the date of grant. The fair value of performance-based awards, which have performance conditions, is based on a Monte Carlo simulation. The fair value of all stock-based compensation is recognized over the period during which an employee is required to provide services in exchange for the award. See Note 10.
Income Taxes	Income Taxes— We have elected on our U.S. federal income tax return for the taxable year ending December 31, 2015 to be treated as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”). To qualify as a REIT, we must distribute at least 90% of our annual REIT taxable income to shareholders, and meet certain organizational and operational requirements, including asset holding requirements. As a REIT, we will generally not be subject to U.S. federal income tax on income that we distribute as dividends to our shareholders. If we fail to qualify as a REIT in any taxable year, we will be subject to U.S. federal income tax, including any applicable alternative minimum tax, on our taxable income at regular corporate income tax rates, and we could not deduct dividends paid to our shareholders in computing taxable income. Any resulting corporate liability could be substantial and could materially and adversely affect our net income and net cash available for distribution to shareholders. Unless we were entitled to relief under certain Code provisions, we also would be disqualified from reelecting to be taxed as a REIT for the four taxable years following the year in which we failed to qualify as a REIT. To maintain REIT status, we must distribute a minimum of 90% of our taxable income. We intend to make regular quarterly dividend payments of all or substantially all of our income to holders of our common stock, and therefore no provision is required in the accompanying Consolidated Financial Statements for U.S. federal income taxes related to the activities of the REIT and its passthrough subsidiaries. We are subject to the statutory requirements of the locations in which we conduct business, and state and local income taxes are accrued as deemed required in the best judgment of management based on analysis and interpretation of respective tax laws. CS&L operates as a real estate investment trust (REIT) for U.S. federal income tax purposes. As a REIT, the Company is generally not subject to U.S. federal income taxes on income generated by its REIT operations, which includes income derived from the Master Lease. We have elected to treat the subsidiaries through which we operate Uniti Fiber and Talk America as taxable REIT subsidiaries (“TRSs”). TRSs enable us to engage in activities that do not result in income that would be qualifying income for a REIT. Our TRSs are subject to U.S. federal, state and local corporate income taxes. Deferred tax assets and liabilities are recognized under the asset and liability method for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax balances are adjusted to reflect tax rates based on currently enacted tax laws, which will be in effect in the years in which the temporary differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the results of operations in the period of the enactment date. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets unless it is more likely than not that such assets will be realized. We recognize the benefit of tax positions that are "more likely than not" to be sustained upon examination based on their technical merit. The benefit of a tax position is measured at the largest amount that has a greater than 50 percent likelihood of being realized upon ultimate settlement. If applicable, we will report tax-related penalties and interest expense as a component of income tax expense. We currently have no liabilities for uncertain income tax positions. The Company will be subject to a federal corporate level tax rate (currently 35%) on any gain recognized from the sale of assets occurring within a specified recognition period after the Spin-Off up to the amount of the built in gain that existed on April 24, 2015, which is based on the fair market value of the assets in excess of the Company’s tax basis as of such date. The Company has no plans to dispose of the assets it acquired through the Spin-Off within the applicable recognition period.
Business Combinations	Business Combinations—In accordance with ASC 805, Business Combinations, we apply the acquisition method of accounting for acquisitions meeting the definition of a business combination, where assets acquired and liabilities assumed are recorded at fair value at the date of each acquisition, and the results of operations are included with those of the Company from the dates of the respective acquisitions. Any excess of the purchase price paid by the Company over the amounts recognized for assets acquired and liabilities assumed is recorded as goodwill. ASC 805 also requires acquirers, among other things, to estimate the acquisition date fair value of any contingent consideration and to recognize any subsequent changes in the fair value of contingent consideration in earnings. When provisional amounts are initially recorded, the Company continues to evaluate acquisitions for a period not to exceed one year after the applicable acquisition date of each transaction to determine whether any additional adjustments are needed to the allocation of the purchase price paid for the assets acquired and liabilities assumed.
Goodwill	Goodwill—Goodwill is recognized for the excess of purchase price over the fair value of net assets of businesses acquired. Goodwill is reviewed for impairment at least annually. In accordance with ASC 350-20, Intangibles-Goodwill and Other, we evaluate goodwill for impairment between annual impairment tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Unless circumstances otherwise dictate, the annual impairment test is performed in the fourth quarter. During the year ended December 31, 2016, no impairment losses were recognized.
Earnings per Share	Earnings per Share—Outstanding restricted stock awards that contain rights to non-forfeitable dividends are deemed to be participating securities, requiring the application of the two-class method of computing basic and dilutive earnings per share. Basic earnings per share includes only the weighted average number of common shares outstanding during the period. Dilutive earnings per share includes the weighted average number of common shares and the dilutive effect of restricted stock and performance-based awards outstanding during the period, when such awards are dilutive. See Note 10.
Concentration of Credit Risks	Concentration of Credit Risks—In connection with the Spin-Off, we entered into the Master Lease agreement with Windstream, pursuant to which all real property associated with the Spin-Off is leased to Windstream and from which substantially all of CS&L’s leasing revenues are currently derived. Windstream is a publicly traded company and is subject to the periodic filing requirements of the Securities Exchange Act of 1934, as amended. Windstream filings can be found at www.sec.gov. Windstream filings are not incorporated by reference in this Annual Report on Form 10-K. Because 87.9% of our revenue for the year ended December 31, 2016 is derived from lease payments by Windstream pursuant to the Master Lease, there could be a material adverse impact on our consolidated results of operations, liquidity and/or financial condition if Windstream experiences operating difficulties and becomes unable to generate sufficient cash to make payments to us. In recent years, Windstream has experienced annual declines in its total revenue and sales. Accordingly, we monitor the credit quality of Windstream through numerous methods, including by (i) reviewing the credit ratings of Windstream by nationally recognized credit rating agencies, (ii) reviewing the financial statements of Windstream that are publicly available and that are required to be delivered to us pursuant to the Master Lease, (iii) monitoring news reports regarding Windstream and its businesses, (iv) conducting research to ascertain industry trends potentially affecting Windstream, and (v) monitoring the timeliness of its payments to us under the Master Lease.
Recently Issued Accounting Standards	Recently Issued Accounting Standards—In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years and early adoption is permitted. We adopted ASU 2016-09 effective April 1, 2016, and will reverse compensation cost of forfeited awards as they occur. At the time of adoption, we had not experienced any forfeited awards and therefore no cumulative-effect adjustment was necessary. In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments (“ASU 2015-16”) which eliminates the prior requirement to recognize measurement-period adjustments to provisional amounts retrospectively. Instead, ASU 2015-16 requires the acquirer to recognize measurement-period adjustments, as well as the impact on earnings of changes in depreciation, amortization and similar items (if any) resulting from the change to the provisional amounts, in the period when the amount of each measurement-period adjustment is determined. As required, the Company adopted the provisions of ASU 2015-16 in the third quarter of its fiscal year ending December 31, 2016 and its adoption did not have a material impact on the Company’s consolidated financial statements. In August 2014, the FASB issued ASU 2014-15, Disclosures of Uncertainties About an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”). ASU 2014-15 provides guidance around management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. Early adoption is permitted. We adopted ASU 2014-15 effective December 31, 2016, and there was no material impact on our financial position, results of operations or cash flows. In January 2017, the FASB issued Accounting Standards Update (“ASU”) No. 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment" ("ASU 2017-04”), which removes the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. ASU 2017-04 is effective for annual and interim periods beginning January 1, 2020, with early adoption permitted, and applied prospectively. The adoption of this guidance is not expected to have a material impact on our financial statements. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (“ASU 2017-01”), in an effort to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. We have elected to early adopt ASU 2017-01 as of January 1, 2017, with prospective application. The adoption of this guidance is not expected to have a material impact on our financial statements. Currently, our real property interest investments will be impacted by ASU 2017-01 as transaction cost associated with the investments will be capitalized as opposed to be recorded as an expense prior to adoption. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 provides guidance on reducing the diversity in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. In addition to other specific cash flow issues, ASU 2016-15 provides clarification on when an entity should separate cash receipts and cash payments into more than one class of cash flows and when an entity should classify those cash receipts and payments into one class of cash flows on the basis of predominance. The new guidance is effective for the fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, and early adoption is permitted. The Company is currently evaluating the impacts the adoption of this accounting standard will have on our financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASC 842”), which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The Company is currently evaluating this guidance to determine the impact it will have on our financial statements by reviewing its existing operating lease contracts, where we are the lessee and service contracts that may include embedded leases. The Company expects a gross-up of its Consolidated Balance Sheets as a result of recognizing lease liabilities and right of use assets, the extent of the impact of a gross-up is under evaluation. The Company does not anticipate material changes to the recognition of operating lease expense in its Consolidated Statements of Income. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). This update outlines a single comprehensive revenue recognition model for entities to follow in accounting for revenue from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. The core principle of the revenue model is that an entity should recognize revenue for the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive for those goods or services. ASU 2014-09 is effective for annual periods beginning after December 15, 2017 and interim periods within those annual periods. Early adoption is permitted for public companies for annual periods beginning after December 15, 2016. The Company intends to adopt the revenue recognition guidance on January 1, 2018. The Company’s implementation efforts include reviewing revenue contracts and the identification of revenue within scope of the guidance. While the Company currently has not identified any material changes in the timing of revenue recognition, the evaluation is ongoing and we are in the process of determining the method of adoption.
Consumer CLEC Business
Summary Of Significant Accounting Policies [Line Items]
Use of Estimates	Use of Estimates —The preparation of financial statements, in accordance with GAAP, requires management to make estimates and assumptions that affect the reported amounts of revenues and expenses. The estimates and assumptions used in the accompanying financial statements are based upon management’s evaluation of the relevant facts and circumstances as of the date of the financial statements. Actual results may differ from the estimates and assumptions used in preparing the accompanying financial statements, and such differences could be material.
Revenue Recognition	Revenue Recognition—Service revenues are primarily derived from providing access to or usage of leased networks and facilities. Service revenues are recognized over the period that the corresponding services are rendered to customers. Revenues derived from other telecommunications services, including broadband, long distance and enhanced service revenues are recognized monthly as services are provided. Sales of customer premise equipment and modems are recognized when products are delivered to and accepted by customers. In assessing collectability of receivables, management considers a number of factors, including historical collection experience, aging of the accounts receivable balances and current economic conditions. When internal collection efforts on accounts have been exhausted, the accounts are written off by reducing the allowance for doubtful accounts. The provision for doubtful accounts, which is included in cost of service, was $111,000 for the period from January 1, 2015 to Spin Date.
Subsequent Events	Subsequent Events—The accompanying financial statements of the Consumer CLEC Business are derived from the consolidated financial statements of Windstream, which issued its audited consolidated financial statements as of and for the year ended December 31, 2015 on February 25, 2016. Accordingly, management has evaluated transactions for consideration as recognized subsequent events in the accompanying financial statement through the date of February 25, 2016. In addition, management has evaluated transactions that occurred as of the issuance of these financial statements on March 7, 2016 for purposes of disclosure of unrecognized subsequent events.