Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) portfolio_segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of Portfolio Segments | portfolio_segment	2
Number of Reportable Segments | portfolio_segment	1
Monthly fee charged Dealer in Portfolio Program	$ 599
One-time enrollment fee in program	$ 9,850
Percentage of first accelerated Dealer Holdback payment retained	50.00%
Percentage of enrollment fee of first accelerated dealer holdback payment	50.00%
Period after Consumer Loan assignment that Dealer Loans written off	120 months
Period after month of purchase that Purchased Loans written off	120 months
Unamortized debt issuance expense	$ 19,000,000	$ 16,100,000
Threshold to determine likelihood of being sustained	50.00%
Employer matching contribution, match percentage	100.00%
Matching contribution	1.00%
Employer matching contribution, additional match percentage	50.00%
Additional matching contribution	5.00%
Maximum matching contribution	3.50%
Recognized compensation expense	$ 3,100,000	2,500,000	$ 2,200,000
Advertising expense	300,000	300,000	$ 200,000
Cash and Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	6,000,000	5,800,000
Restricted Cash And Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	$ 165,100,000	$ 155,300,000
Building [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P40Y
Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P10Y
Data Processing Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P3Y
Software [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P5Y
Office Furniture And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P7Y
Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P7Y
Software Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives	P5Y