Fair Value Of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Dealer Finance Receivables - GO, net	$ 74,753		$ 40,956		$ 5,473	$ 24
Portfolio Term Financings	989,206		1,049,478
Portfolio Warehouse Facilities	145,000		57,200
Senior Secured Notes Payable	193,392		193,320
Other Secured Notes Payable	136,668		117,281
Securitization Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	569,884		677,118
Portfolio Term Residual Financing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	100,000		25,000
Bank Term Financings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	319,322		347,360
Revolving Inventory Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	111,321		91,320
Mortgage Note Payable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	12,397		12,454
Real Estate Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	11,269		11,733
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance Receivables, net	1,461,336	[1]	1,370,800	[1]
Dealer Finance Receivables - GO, net	74,753		40,956
Portfolio Warehouse Facilities	145,000		57,200
Senior Secured Notes Payable	198,392		198,320
Carrying Value [Member] | Securitization Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	569,884		677,118
Carrying Value [Member] | Portfolio Term Residual Financing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	100,000		25,000
Carrying Value [Member] | Bank Term Financings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	319,321		347,360
Carrying Value [Member] | Revolving Inventory Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	111,321		91,320
Carrying Value [Member] | Mortgage Note Payable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	12,397		12,454
Carrying Value [Member] | Real Estate Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	11,269		11,733
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance Receivables, net	1,550,131	[1]	1,441,026	[1]
Dealer Finance Receivables - GO, net	74,753		40,956
Portfolio Warehouse Facilities	145,000		57,200
Senior Secured Notes Payable	222,199		220,135
Fair Value [Member] | Securitization Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	588,176		702,031
Fair Value [Member] | Portfolio Term Residual Financing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	100,000		25,000
Fair Value [Member] | Bank Term Financings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Portfolio Term Financings	319,321		347,360
Fair Value [Member] | Revolving Inventory Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	111,662		91,600
Fair Value [Member] | Mortgage Note Payable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	11,149		11,200
Fair Value [Member] | Real Estate Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Secured Notes Payable	$ 11,237		$ 11,700

[1] Represents finance receivable principal balances, plus accrued interest, less the allowance for credit losses.