Debt (Schedule Of Outstanding Debt Amount) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Balance outstanding	$ 115.9		$ 43.5
Balance outstanding	885.8		853.0
Balance outstanding	350.3		350.3
Restricted cash and cash equivalents pledged as collateral	116.3		92.4
Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Balance outstanding	115.9		43.5
Amount available for borrowing	119.1	[1]	191.5	[1]
Interest rate	2.23%		2.08%
Warehouse Facility II [Member]
Debt Instrument [Line Items]
Balance outstanding	142.1		81.3
Amount available for borrowing	182.9	[1]	243.7	[1]
Loans pledged as collateral	217.2		105.2
Restricted cash and cash equivalents pledged as collateral	4.3		3.0
Interest rate	2.20%		2.22%
Warehouse Facility III [Member]
Debt Instrument [Line Items]
Amount available for borrowing	75.0	[1]	75.0	[1]
Restricted cash and cash equivalents pledged as collateral	0.3		0.4
Interest rate	1.80%		1.82%
Warehouse Facility IV [Member]
Debt Instrument [Line Items]
Balance outstanding	37.6		37.6
Amount available for borrowing	37.4	[1]	37.4	[1]
Loans pledged as collateral	48.3		47.7
Restricted cash and cash equivalents pledged as collateral	3.4		2.5
Interest rate	2.95%		2.96%
Term ABS 2010-1 [Member]
Debt Instrument [Line Items]
Balance outstanding	52.3		80.3
Loans pledged as collateral	96.5		111.6
Restricted cash and cash equivalents pledged as collateral	14.5		12.5
Interest rate	2.64%		2.44%
Term ABS 2011-1 [Member]
Debt Instrument [Line Items]
Balance outstanding	200.5		200.5
Loans pledged as collateral	243.4		243.8
Restricted cash and cash equivalents pledged as collateral	30.4		23.5
Interest rate	2.90%		2.90%
Term ABS 2012-1 [Member]
Debt Instrument [Line Items]
Balance outstanding	201.3		201.3
Loans pledged as collateral	244.0		244.7
Restricted cash and cash equivalents pledged as collateral	28.8		22.3
Interest rate	2.38%		2.38%
Term ABS 2012-2 [Member]
Debt Instrument [Line Items]
Balance outstanding	252.0		252.0
Loans pledged as collateral	310.2		311.9
Restricted cash and cash equivalents pledged as collateral	32.1		26.0
Interest rate	1.63%		1.63%
Senior Notes [Member]
Debt Instrument [Line Items]
Balance outstanding	350.3	[2]	350.3	[2]
Interest rate	9.13%		9.13%
Unamortized debt premium net	$ 0.3		$ 0.3

[1] Availability may be limited by the amount of assets pledged as collateral.

[2] (2) As of March 31, 2013 and December 31, 2012, the outstanding balance presented for the Senior Notes includes a net unamortized debt premium of $0.3 million.