Nature of Business, Interim Financial Data and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Cumulus Media Inc. (and its consolidated subsidiaries, except as the context may otherwise require, "CUMULUS MEDIA," "we," "us," "our," or the "Company") is a Delaware corporation, organized in 2018, and successor to a Delaware corporation with the same name that had been organized in 2002.
Basis of Presentation	Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, the Company's unaudited Condensed Consolidated Financial Statements include all adjustments of a normal recurring nature necessary for a fair statement of the results for the interim periods presented herein. The results for the interim periods are not necessarily indicative of those for the full year. The unaudited Condensed Consolidated Financial Statements herein should be read in conjunction with our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019. The year-end condensed balance sheet data was derived from audited financial statements, but does not include all disclosures required by United States ("U.S.") generally accepted accounting principles ("GAAP").
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures of contingent assets and liabilities. On an on-going basis, the Company evaluates its estimates, including significant estimates related to revenue recognition, bad debts, intangible assets, income taxes, stock-based compensation, contingencies, litigation, valuation assumptions for impairment analysis, certain expense accruals, leases and, if applicable, purchase price allocations. The Company bases its estimates on historical experience and on various assumptions that are believed to be reasonable under the circumstances. We assessed these aforementioned estimates and judgments utilizing information reasonably available to us and considering the unknown future impacts of the novel coronavirus disease ("COVID-19") pandemic. The business and economic uncertainty resulting from the COVID-19 pandemic has made such estimates and assumptions more difficult to calculate. While there was not a material impact to our key estimates as of and for the quarter ended September 30, 2020, our estimates may change based on the magnitude and duration of COVID-19, as well as other factors. Actual amounts and results may differ materially from these estimates.
Comprehensive (Loss) Income	Comprehensive (Loss) Income Comprehensive (loss) income includes net (loss) income and certain items that are excluded from net (loss) income and recorded as a separate component of stockholders' equity. During the nine months ended September 30, 2020 and September 30, 2019, the Company had no items of other comprehensive (loss) income and, therefore, comprehensive (loss) income does not differ from reported net (loss) income.
Assets Held for Sale	Assets Held for Sale Long-lived assets to be sold are classified as held for sale in the period in which they meet all the criteria for the disposal of long-lived assets. The Company measures assets held for sale at the lower of their carrying amount or fair value less cost to sell.
Adoption of New Accounting Standards and Recent Accounting Standards Updates	Adoption of New Accounting Standards ASU 2018-13 - Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). In August 2018, the FASB issued ASU 2018-13, which eliminates, adds, and modifies certain disclosure requirements for fair value measurements as part of its disclosure framework project. ASU 2018-13 is effective for all entities for fiscal years beginning after December 15, 2019, and interim periods therein, but entities are permitted to early adopt either the entire standard or only the provisions that eliminate or modify the requirements. The Company adopted ASU 2018-13 as of January 1, 2020 and there was no material impact to the unaudited Condensed Consolidated Financial Statements. Recent Accounting Standards Updates ASU 2016-13 - Financial Instruments - Credit Losses (Topic 326) ("ASU 2016-13"). In June 2016, the FASB issued ASU 2016-13 which requires entities to estimate loss of financial assets measured at amortized cost, including trade receivables, debt securities and loans, using an expected credit loss model. The expected credit loss differs from the previous incurred losses model primarily in that the loss recognition threshold of "probable" has been eliminated and that expected loss should consider reasonable and supportable forecasts in addition to the previously considered past events and current conditions. Additionally, the guidance requires additional disclosures related to the further disaggregation of information related to the credit quality of financial assets by year of the asset's origination for as many as five years. Entities must apply the standard provision as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The standard was effective for public business entities, excluding Smaller Reporting Companies ("SRC"), for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. The standard is effective for SRCs for fiscal years beginning after December 15, 2022. Early adoption is permitted for annual periods beginning after December 15, 2018, and interim periods within those fiscal years. The Company is currently evaluating the impact of adopting ASU 2016-13 on its unaudited Condensed Consolidated Financial Statements.