Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) portfolio_segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of Reportable Segments | portfolio_segment	1
Monthly fee charged Dealer in Portfolio Program	$ 599
Employer matching contribution, match percentage	100.00%
Matching contribution	4.00%
Employer matching contribution, additional match percentage	50.00%
Additional matching contribution	2.00%
Maximum matching contribution	5.00%
Recognized compensation expense	$ 7,500,000	$ 7,200,000	$ 7,100,000
Threshold to determine likelihood of being sustained	50.00%
Advertising expense	$ 300,000	100,000	$ 300,000
Cash and Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	22,900,000	15,700,000
Restricted Cash And Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	$ 407,900,000	$ 376,900,000
Building [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	40 years
Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	10 years
Data Processing Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	5 years
Office Furniture And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Software Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	five years