Loans Receivable - Loans on Non-accrual Status (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual percent of total loans	0.34%
Non-accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 41,005	$ 55,686
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	100.00%	100.00%
Non-accrual loans \| Single-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 22,285	$ 27,643
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	54.30%	49.60%
Non-accrual loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 0	$ 2,427
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.00%	4.40%
Non-accrual loans \| Construction - custom
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 1,161	$ 0
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	2.80%	0.00%
Non-accrual loans \| Land - acquisition & development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 173	$ 920
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.40%	1.70%
Non-accrual loans \| Land - consumer lot loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 641	$ 787
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	1.60%	1.40%
Non-accrual loans \| Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 1,431	$ 0
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	3.50%	0.00%
Non-accrual loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 8,464	$ 8,971
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	20.60%	16.10%
Non-accrual loans \| Commercial & industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 6,047	$ 14,394
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	14.70%	25.80%
Non-accrual loans \| HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 803	$ 523
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	2.00%	0.90%
Non-accrual loans \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 0	$ 21
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.00%	0.00%

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Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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