Transfers Of Financial Assets , Repurchase price percentage (Details)	3 Months Ended
	Mar. 31, 2012 payment
Minimum [Member] | Less than or equal to 15 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	0
Minimum [Member] | Greater than 15 but less than 64 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	16
Minimum [Member] | Equal to or greater than 64 but less than 120 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	64
Minimum [Member] | 120 or more [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	120
Maximum [Member] | Less than or equal to 15 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	15
Maximum [Member] | Greater than 15 but less than 64 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	63
Maximum [Member] | Equal to or greater than 64 but less than 120 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Receivable Payments Notes Receivable	119
Collateralized receivables [Member] | Less than or equal to 15 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percent	100.00%
Collateralized receivables [Member] | Greater than 15 but less than 64 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percent	90.00%
Collateralized receivables [Member] | Equal to or greater than 64 but less than 120 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percent	65.00%
Collateralized receivables [Member] | 120 or more [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percent	50.00%