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Loans Receivable - Loan Modifications (Details) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Jun. 30, 2018 USD ($) contract | Jun. 30, 2017 USD ($) contract | Jun. 30, 2018 USD ($) contract | Jun. 30, 2017 USD ($) contract
Financing Receivable, Modifications [Line Items] |  |  |  |
Number of Contracts | contract | 0 | 3 | 2 | 18
Recorded Investment | $ | $ 0 | $ 401 | $ 206 | $ 3,853
Single-family residential |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |
Number of Contracts | contract | 0 | 3 | 2 | 16
Recorded Investment | $ | $ 0 | $ 401 | $ 206 | $ 3,586
Commercial real estate |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |
Number of Contracts | contract |  |  | 0 | 2
Recorded Investment | $ |  |  | $ 0 | $ 267

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