Description of Company and Basis of Presentation (Policies)	12 Months Ended
	Sep. 30, 2022
Description of Company and Basis of Presentation [Abstract]
Description of the Business	Description of the Business OneWater Marine Inc. (“OneWater Inc”) was incorporated in Delaware on April 3, 2019 and was a wholly-owned subsidiary of One Water Marine Holdings, LLC (“OneWater LLC”). Pursuant to a reorganization on February 11, 2020 into a holding company structure for the purpose of facilitating an initial public offering (the “IPO”) and related transactions in order to carry on the business of OneWater LLC and its subsidiaries (together with OneWater Inc, the “Company”), OneWater Inc is the holding company and its sole material asset is the equity interest in OneWater LLC. OneWater LLC was organized as a limited liability company under the law of the State of Delaware in 2014 and is the parent company of One Water Assets & Operations (“OWAO”), and its wholly-owned subsidiaries. The Company is one of the largest recreational marine retailers in the United States. The Company engages primarily in the retail sale, brokerage, and service of new and pre-owned boats, motors, trailers, the sale of marine parts and accessories, and offers slip and storage accommodations in certain locations. The Company also arranges related boat financing, insurance, and extended service contracts for customers with third-party lenders and insurance companies. As of September 30, 2022, the Company operates a total of 96 retail locations, 12 distribution centers/warehouses and multiple online marketplaces in 19 states, several of which are in the top twenty states for marine retail expenditures. Operating results are generally subject to seasonal variations. Demand for products is generally highest during the third and fourth quarters of the fiscal year and, accordingly, revenues are generally expected to be higher during these periods. General economic conditions and consumer spending patterns can negatively impact the Company’s operating results. Unfavorable local, regional, national, or global economic developments, global public health concerns, including the COVID-19 pandemic, or uncertainties could reduce consumer spending and adversely affect the Company’s business. Consumer spending on discretionary goods may also decline as a result of lower consumer confidence levels, even if prevailing economic conditions are otherwise favorable. Economic conditions in areas in which the Company operates, particularly in the Southeast, can have a major impact on the Company’s overall results of operations. Local influences such as corporate downsizing, inclement weather such as hurricanes and other storms, environmental conditions, and other events could adversely affect the Company’s operations in certain markets and in certain periods. Any extended period of adverse economic conditions or low consumer confidence is likely to have a negative effect on the Company’s business. Sales of new boats from the Company’s top ten brands represent approximately 41.8%, 42.9% and 41.1% of total sales for the years ended September 30, 2022, 2021 and 2020, respectively, making them major suppliers of the Company. Of this amount, Malibu Boats, Inc, including its brands Malibu, Axis, Cobalt, Pursuit, Maverick, Hewes, Cobia and Pathfinder accounted for 15.6%, 17.0% and 17.0% of our consolidated revenue for the years ended September 30, 2022, 2021 and 2020, respectively. As is typical in the industry, the Company contracts with most manufacturers under renewable annual dealer agreements, each of which provides the right to sell various makes and models of boats within a given geographic region. Any change or termination of these agreements, or the agreements discussed above, for any reason, or changes in competitive, regulatory, or marketing practices, including rebate or incentive programs, could adversely affect results of operations. Pre-owned boats are usually trade-ins from retail customers who are purchasing a boat from the Company.
Initial Public Offering	Initial Public Offering On February 11, 2020, OneWater Inc completed its IPO of 5,307,693 shares of Class A common stock, par value $0.01 per share (the “Class A common stock”), which includes the exercise in full of the underwriters’ option to purchase up to 692,308 additional shares of Class A common stock pursuant to the Underwriting Agreement, at a price to the public of $12.00 per share. After deducting underwriting discounts and commissions, OneWater Inc received net proceeds of $59.2 million. OneWater Inc contributed all of the net proceeds of the IPO received to OneWater LLC in exchange for limited liability company interests in OneWater LLC (“LLC Units”). OneWater LLC used the net proceeds, cash on hand and borrowings under its Amended and Restated Credit and Guaranty Agreement by and among OneWater Inc, OneWater LLC and its subsidiaries, with Goldman Sachs Specialty Lending Group, L.P. (i) to pay $3.2 million to one Legacy Owner in exchange for the surrender of a preferred distribution right and (ii) to contribute cash to OWAO in exchange for additional units therein, and OWAO used such cash to fully redeem the preferred interest in subsidiary held by Goldman Sachs & Co. LLC and certain of its affiliates (collectively, “Goldman”) and affiliates of The Beekman Group (“Beekman”). Additionally, the Company provided certain of the existing owners of OneWater LLC, including Goldman and Beekman and certain members of the Company’s management team, the right to receive a tax distribution to cover taxable income arising as a result of OneWater LLC’s operating income through the period ending on the date of the closing of the IPO.
September Offering	September Offering On September 22, 2020, OneWater Inc completed an underwritten public offering (the “September Offering”) of 3,170,868 shares of Class A common stock, at a public offering price of $20.00 per share, less underwriting discounts and commissions. OneWater Inc sold 425,000 shares of Class A common stock, and certain stockholders of the Company (the “Selling Stockholders”) sold 2,745,868 shares of Class A common stock. In connection with the September Offering, Goldman granted the underwriters a 30-day option to purchase up to an additional 475,630 shares of the Company’s Class A common stock (the “Optional Shares”). On September 29, 2020, the underwriters notified OneWater Inc and Goldman of their intent to purchase an additional 387,458 Optional Shares. The sale of the Optional Shares closed on October 2, 2020. The Company did not receive any proceeds from the sale of the Optional Shares or the Class A common stock sold by Selling Stockholders. After deducting underwriting discounts and commissions, OneWater Inc received net proceeds of $8.1 million. OneWater Inc contributed all of the net proceeds of the September Offering received to OneWater LLC in exchange for LLC Units. OneWater LLC used the net proceeds for general corporate purposes.
Principles of Consolidation	Principles of Consolidation As the sole managing member of OneWater LLC, OneWater Inc operates and controls all of the businesses and affairs of OneWater LLC, and through OneWater LLC and its wholly-owned subsidiaries, as well as majority-owned subsidiaries over which the Company exercises control, conducts its business. As a result, OneWater Inc consolidates the financial results of OneWater LLC and its subsidiaries and reports non-controlling interests related to the portion of units of OneWater LLC (the “OneWater LLC Units”) not owned by OneWater Inc, which will reduce net income attributable to OneWater Inc’s Class A stockholders. As of September 30, 2022, OneWater Inc owned 90.9% of the economic interest of OneWater LLC. Commencing December 31, 2021, the Company owns 80% of the economic interest of Quality Assets and Operations, over which the Company exercises control and the minority interest in this subsidiary has been recorded accordingly. See note 4 for additional information regarding the acquisition.
Basis of Financial Statement Preparation	Basis of Financial Statement Preparation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All adjustments, consisting of only normal recurring adjustments considered necessary for fair presentation, have been reflected in these consolidated financial statements. All intercompany transactions have been eliminated in consolidation. The Company operates on a fiscal year basis with the first day of the fiscal year being October 1, and the last day of the fiscal year ending on September 30.