Loans Receivable - Loans on Non-accrual Status (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual percent of total loans	0.41%	0.46%
Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 45,520	$ 49,580
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	100.00%	100.00%
Single-family residential \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 26,219	$ 27,930
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	57.70%	56.30%
Construction \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 364	$ 0
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.80%	0.00%
Construction - custom \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 0	$ 91
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.00%	0.20%
Land - acquisition & development \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 1,326	$ 296
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	2.90%	0.60%
Land - consumer lot loans \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 976	$ 605
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	2.10%	1.20%
Multi-family \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 250	$ 139
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.50%	0.30%
Commercial real estate \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 8,241	$ 11,815
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	18.10%	23.80%
Commercial & industrial \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 7,596	$ 8,082
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	16.70%	16.30%
HELOC \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 476	$ 531
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	1.00%	1.10%
Consumer \| Non-Accrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 72	$ 91
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.20%	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://www.xbrl.org/2003/role/presentationRef
-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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