Summary of Significant Accounting Policies - Summary of Estimated Useful Lives of Assets (Details)	Sep. 30, 2025
Company vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Buildings and improvements \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	10 years
Buildings and improvements \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	39 years
Machinery and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Machinery and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	7 years
Office equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Office equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life (in years)	7 years

OneWater Marine Inc. 10-K