Organization, Consolidation and Presentation	3 Months Ended
Organization, Consolidation and Presentation	Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure	ORGANIZATION, CONSOLIDATION AND PRESENTATION (a)Business American Coastal Insurance Corporation (referred to in this document as we, our, us, the Company or ACIC) is a property and casualty insurance holding company that sources, writes and services residential commercial and casualty insurance policies using a network of agents and one wholly-owned insurance subsidiary, American Coastal Insurance Company (AmCoastal), acquired via merger on April 3, 2017. The Company previously wrote insurance through Interboro Insurance Company (IIC); however, on April 1, 2025, the Company completed the sale of IIC. The details of this transaction are described below. The Company's other subsidiaries include Skyway Underwriters, LLC, a managing general agent that provides technological and distribution services to the Company's insurance company; AmCo Holding Company, LLC (AmCo) which is a holding company subsidiary that consolidates its respective insurance company; BlueLine Cayman Holdings (BlueLine), which reinsures portfolios of excess and surplus policies; and Shoreline Re, which provides a portion of the reinsurance protection purchased by the Company's insurance subsidiary where management deems prudent. The Company also has several subsidiaries in run-off including United Insurance Management, L.C. (UIM), a managing general agent; Skyway Claims Services, LLC (SCS), which previously provided claims adjusting services to the Company's insurance companies; Skyway Reinsurance Services, LLC, which previously provided reinsurance brokerage services for the Company's insurance companies; and Skyway Legal Services, LLC (SLS), which previously provided claims litigation services to the Company's insurance companies. On May 9, 2024, the Company entered into a Stock Purchase Agreement (the "Sale Agreement") with Forza Insurance Holdings, LLC (Forza) in which the Company agreed to sell and Forza agreed to acquire 100% of the issued and outstanding stock of IIC. Forza’s application to acquire IIC was approved by the New York Department of Financial Services (NYDFS) on February 13, 2025 and the sale closed on April 1, 2025. The aggregate purchase price for the shares was equal to IIC's shareholders' equity under U.S. generally accepted accounting principles (“GAAP”) on the closing date. IIC results of operations and assets and liabilities are captured within discontinued operations and are discussed in Note 4 of the Notes to Unaudited Condensed Consolidated Financial Statements below. The Company's primary product is commercial residential property insurance in Florida. As a result of the Sale Agreement described above and the resulting in classification of IIC as discontinued operations, the remaining activity captured within continuing operations supports only the Company's commercial residential insurance offerings. Given this fact pattern, the Company conducts operations under one reportable segment. The Company's chief operating decision maker (CODM) is its President and Chief Executive Officer (CEO). (b)Consolidation and Presentation The Company prepares its unaudited condensed consolidated interim financial statements in conformity with U.S. generally accepted accounting principles (GAAP). The Company has condensed or omitted certain information and footnote disclosures normally included in the annual consolidated financial statements presented in accordance with GAAP. In management's opinion, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, including normal recurring items, considered necessary for a fair presentation of interim periods. The Company includes all of its subsidiaries in its consolidated financial statements, eliminating intercompany balances and transactions during consolidation. As described in Note 4, the Company's former subsidiary, IIC, qualified as discontinued operations. The Company's unaudited condensed consolidated interim financial statements and footnotes should be read in conjunction with the Company's consolidated financial statements and footnotes in the Company's Annual Report on Form 10-K for the year ended December 31, 2024. While preparing the Company's unaudited condensed consolidated financial statements, the Company makes estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, as well as reported amounts of revenues and expenses during the reporting period. Accordingly, actual results could differ from those estimates. Reported amounts that require the Company to make extensive use of estimates include its reserves for unpaid losses and loss adjustment expenses, investments and goodwill. Except for the captions on the Company's Unaudited Condensed Consolidated Balance Sheets and Unaudited Condensed Consolidated Statements of Comprehensive Income, the Company generally uses the term loss(es) to collectively refer to both loss and loss adjustment expenses. The Company's results of operations and cash flows as of the end of the interim periods reported herein do not necessarily indicate the Company's results for the remainder of the year or for any other future period. Operating segments are components of the Company's business about which separate financial information is available and evaluated by the Company's CODM in decisions regarding resource allocations and financial performance assessments. Generally, financial information is required to be reported on the basis that is used internally for evaluating segment performance and deciding how to allocate resources to each segment. Segments are determined based on differences in products, internal reporting, and how operational decisions are made. As described above, as a result of entering into definitive agreements to sell IIC, the Company discloses one reportable operating segment, which consists of its commercial lines business. The Company's CODM is its President and CEO. The CODM uses net income that is also reported on the Consolidated Statements of Comprehensive Income to make decisions on how to allocate resources, for example deciding whether to reinvest profits for items such as product development or acquisitions, or whether to pay dividends. Net income is used to monitor budget versus actual results. Net income is also used in competitive analysis by benchmarking against the Company's peers. This analysis is used in assessing performance of the Company's operating segment and in establishing targets for management. In addition, the Company's measure of segment assets is reported on the Consolidated Balance Sheets as total assets. The accounting policies of the Company's operating segment are the same as those described in the Company's summary of significant accounting policies in the Company's Annual Report on Form 10-K for the year ended December 31, 2024. Revenue, profit or loss and significant segment expenses can be seen on the Consolidated Statements of Comprehensive Income. Additional reconciliation of certain expenses can be seen within Note 3, below.