Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) portfolio_segment segment	Dec. 31, 2015 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | segment	1
Uninsured cash and cash equivalents	$ 157.4	$ 6.0
Number of portfolio segments | portfolio_segment	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	$ 231.3	$ 165.1