Basis of Presentation and Significant Accounting Policies - Activity in Polaris Accrued Warranty Reserve (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Activity in Product Warranty Reserve [Roll Forward]
Balance at beginning of period	$ 153.4	$ 174.1	$ 162.8	$ 181.1
Additions charged to expense	38.5	45.8	101.2	132.7
Warranty claims paid, net	(37.7)	(44.7)	(109.8)	(138.6)
Balance at end of period	$ 154.2	$ 175.2	$ 154.2	$ 175.2