Finance Receivables Finance Receivables Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal Collection and Recoveries on Receivables	$ 1,096,275	$ 1,015,918
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-Acquisition Finance Receivables, Carrying Value	1,579,955		1,958,204	4,027,361
Post-Acquisition Finance Receivables, Carrying Value	9,433,105		8,830,914	5,313,899
Finance Receivables Purchased	1,358,710	1,395,757
Financing Receivable, Allowance for Credit Losses, Charge-offs	(131,542)	(51,058)
Change in Carrying Value Adjustment	(28,468)	(82,326)
Principal Collection and Recoveries on Receivables	(974,758)	(919,865)
Financing Receivable, Gross	11,013,060	9,683,768	10,789,118	9,341,260
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance Receivables Purchased	1,040,376
Principal Collection and Recoveries on Receivables	(717,639)
Financing Receivable, Gross	$ 882,736		$ 559,999