Finance Receivables - Changes In The Allowance For Finance Credit Losses On Finance Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 198,581	$ 189,885	$ 192,471
Provision for credit losses	181,870	134,536	106,870
Charge-offs	(139,944)	(173,358)	(154,441)
Recoveries	49,825	47,518	44,985
Balance, end of period	390,936	198,581	189,885
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	100,604
Balance, end of period		100,604
Retail
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	188,501	182,098	186,254
Provision for credit losses	175,225	132,243	105,292
Charge-offs	(137,371)	(173,358)	(154,433)
Recoveries	49,825	47,518	44,985
Balance, end of period	371,738	188,501	182,098
Retail | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	95,558
Balance, end of period		95,558
Wholesale
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	10,080	7,787	6,217
Provision for credit losses	6,645	2,293	1,578
Charge-offs	(2,573)	0	(8)
Recoveries	0	0	0
Balance, end of period	19,198	10,080	$ 7,787
Wholesale | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 5,046
Balance, end of period		$ 5,046