Organization and Significant Accounting Policies - Activity in Polaris Accrued Warranty Reserve (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity in Product Warranty Reserve [Roll Forward]
Balance at beginning of year	$ 119,274	$ 56,474	$ 53,104
Additions to reserve through acquisitions	0	147	250
Additions charged to expense	145,705	194,996	73,716
Less: warranty claims paid	(141,139)	(132,343)	(70,596)
Balance at end of year	$ 123,840	$ 119,274	$ 56,474