Loan Loss Allowance and Credit Quality - Summary of Loan Modification Accounted as TDRs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014 Contract	Mar. 31, 2013 Contract
Retail Installment Contracts
Financing Receivable Modifications [Line Items]
Outstanding recorded investment before TDR	$ 624,009	$ 290,861
Outstanding recorded investment after TDR	581,053	288,841
Number of contracts	39,229	20,474
Unsecured Consumer Loans
Financing Receivable Modifications [Line Items]
Outstanding recorded investment before TDR	11,495
Outstanding recorded investment after TDR	$ 11,336
Number of contracts	14,829

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953676-111524

+ Details

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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