Acquisitions and Dispositions - Dispositions (Details) $ in Thousands		12 Months Ended
	Sep. 30, 2023 USD ($) location	Sep. 30, 2025 USD ($) location	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($) location
Business Combination [Line Items]
Pre-tax gain (loss) on sale of business		$ 0	$ 0	$ (750)
Number of retail locations | location		95
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Roscioli Yachting Center
Business Combination [Line Items]
Term of contract		10 years
Dealerships | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Roscioli Yachting Center
Business Combination [Line Items]
Pre-tax gain (loss) on sale of business	$ 200
Gain (loss) on sale and leaseback transaction				$ 0
Dealerships | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Lookout Marine
Business Combination [Line Items]
Pre-tax gain (loss) on sale of business	$ (1,000)
Number of retail locations | location	2			2