Finance Receivables Finance Receivables Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal Collection and Recoveries on Receivables			$ 2,040,006	$ 1,880,176
Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-Acquisition Finance Receivables, Carrying Value					3,357,341	4,027,361	6,337,075	7,299,963
Post-Acquisition Finance Receivables, Carrying Value					6,326,427	5,313,899	2,004,813	923,713
Finance Receivables, Carrying Value	9,683,768	8,341,888	9,341,260	8,223,676
Finance Receivables Purchased	1,489,402	1,349,222	2,885,159	2,487,143
Financing Receivable, Allowance for Credit Losses, Charge-offs	(52,741)	(6,738)	(103,799)	(8,547)
Change in Carrying Value Adjustment	(36,368)	(130,266)	(118,694)	(295,546)
Principal Collection and Recoveries on Receivables	(931,614)	(859,565)	(1,851,479)	(1,712,185)
Notes, Loans and Financing Receivable, Gross	10,152,447	8,694,541	10,152,447	8,694,541
Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes, Loans and Financing Receivable, Gross	$ 127,560		$ 127,560