Loans Receivable - Loans on Non-accrual Status (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual percent of total loans	0.53%	0.46%
Non-accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 60,584	$ 49,580
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	$ 26,119	$ 27,930
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	43.10%	56.30%
Non-accrual loans \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 1,841	$ 0
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	3.00%	0.00%
Non-accrual loans \| Construction - custom
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 0	$ 91
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.00%	0.20%
Non-accrual loans \| Land - acquisition & development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 1,757	$ 296
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	2.90%	0.60%
Non-accrual loans \| Land - consumer lot loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 642	$ 605
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	1.10%	1.20%
Non-accrual loans \| Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 0	$ 139
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.00%	0.30%
Non-accrual loans \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 9,684	$ 11,815
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	16.00%	23.80%
Non-accrual loans \| Commercial & industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 19,876	$ 8,082
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	32.80%	16.30%
Non-accrual loans \| HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 637	$ 531
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	1.10%	1.10%
Non-accrual loans \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 28	$ 91
Ratio of non-accrual loan by portfolio segment to total loans on non-accrual status	0.00%	0.20%

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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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