Loan Servicing Rights - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Transfers and Servicing [Abstract]
Constant prepayment rates (as a percent)	12.00%
Discount rate (as a percent)	11.90%
Loan servicing rights, valuation allowance	$ 43	$ 81	$ 8	$ 13

Discount rate which is used to value residual cash flows generated by financial assets of the securitization, asset-backed financing arrangement, or similar transfer for initial fair value measurement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=82924980&loc=d3e107207-111719

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Estimated rate of prepayment of principal on financial assets for initial fair value measurement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=82924980&loc=d3e107207-111719

+ Details

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Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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- Definition

Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122739-111746

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant