Fair Value of Financial Instruments (Servicing Rights) (Details)	6 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Minimum
Servicing Assets at Fair Value [Line Items]
Discount rate	30.00%	30.00%
Cost of service	0.04%	0.04%
Renewal rate	41.06%	41.06%
Default rate	10.63%	10.63%
Maximum
Servicing Assets at Fair Value [Line Items]
Discount rate	30.00%	30.00%
Cost of service	0.13%	0.13%
Renewal rate	51.83%	51.83%
Default rate	10.92%	10.92%
Weighted Average
Servicing Assets at Fair Value [Line Items]
Discount rate	30.00%	30.00%
Cost of service	0.13%	0.12%
Renewal rate	51.01%	49.59%
Default rate	10.67%	10.70%

Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Cost of Service

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- Definition

Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Default Rate

+ References

No definition available.

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- Definition

Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Renewal Rate

+ References

No definition available.

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- Definition

Discount rate used to estimate the fair value of servicing assets and servicing liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122596-111746

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- Definition

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.

+ References

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