Derivatives (Details) (USD $) In Thousands, unless otherwise specified					6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Interest rate derivatives designated as cash flow hedges Securitization No. 1 London Interbank Offered Rate (LIBOR)	Jun. 30, 2014 Not Designated as Hedging Instrument Securitization No. 1 London Interbank Offered Rate (LIBOR)	Jun. 30, 2014 Cash Flow Hedging Interest Rate Contract Interest rate derivatives designated as cash flow hedges Securitization No. 2	Jun. 30, 2014 Cash Flow Hedging Interest Rate Contract Interest rate derivatives designated as cash flow hedges Securitization No. 2 Minimum	Jun. 30, 2014 Cash Flow Hedging Interest Rate Contract Interest rate derivatives designated as cash flow hedges Securitization No. 2 Maximum	Jun. 30, 2014 Cash Flow Hedging Interest Rate Contract Interest rate derivatives designated as cash flow hedges Derivative Liabilities Securitization No. 2
Derivatives, Fair Value [Line Items]
Current Notional Amount					$ 422,276
Future Maximum Notional Amount					422,276
Floating Rate					1M LIBOR
Fixed Rate						1.26%	1.28%
Derivative liabilities	$ 4,757	$ 39,992						$ 4,757
Derivative, Basis Spread on Variable Rate