Guarantees - Indemnification, Representations and Warranties related to loans sold - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Securitization \| Guarantee on loans sold or serviced with representation and warranties
Guarantor Obligations
Repurchased Loans	$ 0	$ 2,000,000	$ 0	$ 12,000,000

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