Loan Receivables Held for Sale - Principal balances of sold loan receivables (Details) - Bank Partners - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Total principal balance	$ 322,661		$ 322,661		$ 305,748
Delinquent loans (unpaid principal balance)	14,926		14,926		$ 20,409
Net charge-offs (unpaid principal balance)	$ 1,787	$ 1,353	$ 4,712	$ 3,005

This is the amount of the financial instruments that are considered delinquent (past due) at the end of the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (e)(4)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719

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- Definition

Net credit losses are charge-offs and are based on total loans outstanding during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (e)(5)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719

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- Definition

Amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction that have been derecognized. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719

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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

No definition available.

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