Accounting Policies (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption	$ 342,413		$ 334,392	$ 309,398	$ 301,728
Finance receivable, allowance for credit losses	26,840		29,232	23,637	21,187
Off-balance sheet, credit loss, liability	993
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption	$ 51,263		41,899	$ 37,441	$ 33,218
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Finance receivable, allowance for credit losses		$ (1,300)
Off-balance sheet, credit loss, liability		1,100
Deferred tax liabilities, net		41
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption			120
Finance receivable, allowance for credit losses			(1,300)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption			$ 120
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption		$ 120