Fair Value Measurements Fair Value Unobservable Level 3 Measurements (Details) - Fair Value, Inputs, Level 3	3 Months Ended
Mar. 31, 2018
Discounted Cash Flow \| Servicing Contracts
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate	11.00%
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Prepayment Speed	9.00%
Appraisals/Discounted Cash Flow \| Impaired Finance Receivable
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate	28.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Discount rate which is used to value residual cash flows generated by financial assets of a securitization, asset-backed financing arrangement, or similar transfer regardless of when the transfer occurred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=82924980&loc=d3e107314-111719

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- Definition

Estimated rate of prepayment of principal on financial assets regardless of when the transfer occurred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=82924980&loc=d3e107314-111719

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