Activity in Polaris Accrued Warranty Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Product Warranty Liability [Line Items]
Balance at beginning of year	$ 38,685	$ 31,862	$ 44,355	$ 32,651
Additions to warranty reserve through acquisitions				2,018
Additions charged to expense	12,101	13,155	29,140	29,672
Warranty claims paid	(9,215)	(8,293)	(31,924)	(27,617)
Balance at end of year	$ 41,571	$ 36,724	$ 41,571	$ 36,724