Financing Agreement - Additional Information (Details) - USD ($)	1 Months Ended
	Dec. 31, 2013	Dec. 31, 2010	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 31, 2018	Jul. 02, 2018	Dec. 31, 2017	Sep. 30, 2015
Line of Credit Facility [Line Items]
Letter of credit outstanding			$ 21,637,000
Debt outstanding from dealers			1,884,131,000
Long-term debt			$ 1,600,183,000	$ 1,862,631,000				$ 883,000,000
Maximum
Line of Credit Facility [Line Items]
Aggregate repurchase obligation			15.00%
Master Notes | Senior Unsecured Notes, 3.81 Percent, Due May 2018
Line of Credit Facility [Line Items]
Issuance of senior notes		$ 25,000,000
Maturity date		May 31, 2018
Master Notes | Senior Unsecured Notes, 4.60 Percent, Due May 2021
Line of Credit Facility [Line Items]
Issuance of senior notes		$ 75,000,000
Maturity date		May 31, 2021
Master Notes | Senior Unsecured Notes 3.13 Percent Due December 2020
Line of Credit Facility [Line Items]
Issuance of senior notes	$ 100,000,000
Maturity date	Dec. 31, 2020
Master Notes | Senior Unsecured Notes 4.23 Percent, Due July 2028
Line of Credit Facility [Line Items]
Maturity date	Jul. 31, 2028
Senior Notes | Senior Unsecured Notes, 4.60 Percent, Due May 2021
Line of Credit Facility [Line Items]
Long-term debt			$ 75,000,000	75,000,000
Senior Notes | Senior Unsecured Notes 3.13 Percent Due December 2020
Line of Credit Facility [Line Items]
Long-term debt			100,000,000	100,000,000
Senior Notes | Senior Unsecured Notes 4.23 Percent, Due July 2028
Line of Credit Facility [Line Items]
Long-term debt			350,000,000	350,000,000	$ 350,000,000
Notes payable and other | Mortgages
Line of Credit Facility [Line Items]
Long-term debt			9,666,000						$ 14,500,000
Long-term Debt
Line of Credit Facility [Line Items]
Revolving loan facility, maximum capacity						$ 1,180,000,000
Long-term line of credit			1,000,000,000	$ 1,150,000,000
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months			59,000,000
Revolving loan facility
Line of Credit Facility [Line Items]
Revolving loan facility, maximum capacity						$ 700,000,000
Boat Holdings, LLC | Notes Payable, Other Payables [Member]
Line of Credit Facility [Line Items]
Long-term debt			$ 71,722,000				$ 76,733,000
TCF Financial Corporation | Maximum
Line of Credit Facility [Line Items]
Aggregate repurchase obligation			100.00%
TCF [Member] | Maximum
Line of Credit Facility [Line Items]
Aggregate repurchase obligation			100.00%
Polaris Acceptance
Line of Credit Facility [Line Items]
Aggregate repurchase obligation, amount			$ 180,557,000