Activity in Polaris Accrued Warranty Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Product Warranty Liability [Line Items]
Balance at beginning of year	$ 44,355	$ 32,651
Additions charged to expense	8,392	8,925
Warranty claims paid	(12,317)	(10,547)
Balance at end of year	$ 40,430	$ 31,029