Finance Receivables Finance Receivables Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal Collection and Recoveries on Receivables			$ 3,049,533	$ 2,816,607
Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-Acquisition Finance Receivables, Carrying Value					2,812,205	4,027,361	5,471,957	7,299,963
Post-Acquisition Finance Receivables, Carrying Value					7,340,242	5,313,899	3,222,584	923,713
Finance Receivables, Carrying Value					10,152,447	9,341,260	8,694,541	8,223,676
Finance Receivables Purchased	1,477,860	1,358,115	4,363,019	3,845,258
Financing Receivable, Allowance for Credit Losses, Charge-offs	(82,255)	(20,246)	(186,054)	(28,793)
Change in Carrying Value Adjustment	(26,269)	(87,125)	(144,963)	(382,671)
Principal Collection and Recoveries on Receivables	(916,794)	(875,993)	(2,768,273)	(2,588,178)
Financing Receivable, Gross	10,604,989	9,069,292	10,604,989	9,069,292
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance Receivables Purchased	410,344		584,140
Principal Collection and Recoveries on Receivables	(253,491)		(299,727)
Financing Receivable, Gross	$ 284,413		$ 284,413		$ 127,560