Derivative and Hedging Instruments (Schedule of Terms of Interest Rate Cap Agreements) (Details) - USD ($)		6 Months Ended		12 Months Ended
		Jun. 30, 2015		Dec. 31, 2014	Jun. 11, 2015	May. 19, 2015
Derivative [Line Items]
Interest rate caps, fair value of less than $0.1 million		$ 100,000		$ 100,000
Warehouse Facility II [Member]
Derivative [Line Items]
Debt facility financing amount		400,000,000	[1],[2]			$ 325,000,000
Warehouse Facility II [Member] | 5.50% Cap Interest Rate [Member]
Derivative [Line Items]
Debt facility financing amount		$ 400,000,000		$ 325,000,000
Start				Dec. 01, 2014
End		Jun. 01, 2016		Jun. 01, 2016
Notional		$ 325,000,000		$ 325,000,000
Cap Interest Rate	[3]	5.50%		5.50%
Term ABS 2012-2 [Member]
Derivative [Line Items]
Debt facility financing amount	[1]	$ 252,000,000
Start		Dec. 01, 2014
Warehouse Facility IV [Member]
Derivative [Line Items]
Debt facility financing amount	[1],[2]	$ 75,000,000
Notional		75,000,000		$ 75,000,000
Warehouse Facility IV [Member] | 5.50% Cap Interest Rate [Member]
Derivative [Line Items]
Debt facility financing amount		$ 75,000,000		$ 75,000,000
Start		Aug. 01, 2011		Aug. 01, 2011
End		Sep. 01, 2015		Sep. 01, 2015
Notional		$ 7,600,000		$ 29,300,000
Cap Interest Rate	[3]	5.50%		5.50%
Warehouse Facility IV Member Starting March 2014 [Member] | 5.50% Cap Interest Rate [Member]
Derivative [Line Items]
Start		Mar. 01, 2014		Mar. 01, 2014
End		Mar. 01, 2017		Mar. 01, 2017
Notional		$ 67,400,000		$ 45,700,000
Cap Interest Rate	[3]	5.50%		5.50%
Warehouse Facility V [Member]
Derivative [Line Items]
Debt facility financing amount		$ 100,000,000	[1],[2]		$ 75,000,000
Notional		75,000,000
Warehouse Facility V [Member] | 5.50% Cap Interest Rate [Member]
Derivative [Line Items]
Notional		$ 18,700,000
Cap Interest Rate	[3]	5.50%
Warehouse Facility V [Member] | 5.00% Cap Interest Rate [Member]
Derivative [Line Items]
Debt facility financing amount		$ 100,000,000		$ 75,000,000
Start		Jun. 01, 2012		Jun. 01, 2012
End		Jul. 01, 2015		Jul. 01, 2015
Notional		$ 56,300,000		$ 56,300,000
Cap Interest Rate	[3]	5.00%		5.00%

[1] Financing made available only to a specified subsidiary of the Company.

[2] Interest rate cap agreements are in place to limit the exposure to increasing interest rates.

[3] Rate excludes the spread over the LIBOR rate or the commercial paper rate, as applicable.