Debt Obligations (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Mar. 31, 2007	Jul. 31, 2005	Mar. 22, 2007	Jul. 12, 2005
Debt Instrument [Line Items]
Issuance Dates	Mar. 22, 2007	Jul. 12, 2005
Total amount of loans included in initial securitization			$ 116.5	$ 141.0
Total amount of bonds issued to fund initial securitization			101.9	118.4
Expected weighted average maturity	4 years 10 months 10 days	4 years 7 months 28 days
Bonds maturity term	2008 through 2017	2006 through 2015
Class A-1 [Member]
Debt Instrument [Line Items]
Amount of bonds			28.9	36.3
Coupon rate			5.484%	4.23%
Class A-2 [Member]
Debt Instrument [Line Items]
Amount of bonds			23.4	27.4
Coupon rate			5.232%	4.42%
Class A-3 [Member]
Debt Instrument [Line Items]
Amount of bonds			24.5	27.3
Coupon rate			5.593%	4.80%
Class A-4 [Member]
Debt Instrument [Line Items]
Amount of bonds			$ 25.1	$ 27.4
Coupon rate			5.846%	5.20%