Financial Services Arrangements - Financial Information for Polaris Acceptance Reflecting Effects of Securitization Facility (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Net income	$ 124,800	$ 324,000	$ 335,300
Total Assets	4,632,700	4,430,500
Total Liabilities and Partners' Capital	4,632,700	4,430,500
Polaris Acceptance
Schedule of Investments [Line Items]
Revenues	44,700	79,300	72,100
Interest and operating expenses	7,600	14,400	11,800
Net income	37,100	64,900	$ 60,300
Finance receivables, net	392,700	687,700
Other assets	13,900	100
Total Assets	406,600	687,800
Notes Payable	248,400	463,100
Other liabilities	39,400	3,400
Partners' capital	118,800	221,300
Total Liabilities and Partners' Capital	$ 406,600	$ 687,800
Maximum
Schedule of Investments [Line Items]
Aggregate repurchase obligation	15.00%
Polaris Acceptance | Maximum
Schedule of Investments [Line Items]
Aggregate repurchase obligation	15.00%