Summary of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 portfolio_segment segment	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments	1
Uninsured cash and cash equivalents	$ 86.2	$ 5.8
Number of portfolio segments	2
Period after Consumer Loan assignment that Dealer Loans written off	120 months
Period after month of purchase that Purchased Loans written off	120 months
Restricted Cash and Cash Equivalents [Member]
Summary Of Significant Accounting Policies [Line Items]
Uninsured cash and cash equivalents	$ 196.9	$ 155.3