Finance Receivables - Finance Receivables, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 6,833,944	$ 7,572,947	$ 7,411,816	$ 7,157,557	$ 7,008,801
Allowance for credit losses	(390,936)	(198,581)	(189,885)	(192,471)	(173,343)
Total allowance for credit losses	6,443,008	7,374,366	7,221,931	6,965,086	6,835,458
United States
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,587,764
Canada
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	246,180
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,344,195	6,416,428	6,328,201	6,140,600	5,982,211
Allowance for credit losses	(371,738)	(188,501)	(182,098)	(186,254)
Retail | United States
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,128,269	6,180,236	6,103,378	5,901,002	5,769,410
Retail | Canada
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	215,926	236,192	224,823	239,598	212,801
Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	489,749	1,156,519	1,083,615	1,016,957	1,026,590
Allowance for credit losses	(19,198)	(10,080)	(7,787)	(6,217)
Wholesale | United States
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	459,495	1,067,880	1,007,956	939,621	961,150
Wholesale | Canada
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 30,254	$ 88,639	$ 75,659	$ 77,336	$ 65,440