Restructuring and Impairment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges	$ 6.6	$ 0.4	$ 14.0	$ 2.3
Restructuring and Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges				1.2
New Boat Cost of Sales
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges				1.1
Dealerships
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges	6.0		6.0	1.2
Distribution
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges	$ 0.6	$ 0.4	$ 8.0	$ 1.1