Loans Receivable - Loans on Non-accrual Status (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 47,349	$ 67,810
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	100.00%	100.00%
Single-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 36,707	$ 59,074
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	77.50%	87.10%
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 0	$ 754
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.00%	1.10%
Construction - custom
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 506	$ 732
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	1.10%	1.10%
Land - acquisition & development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 427	$ 0
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.90%	0.00%
Land - consumer lot loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 1,105	$ 1,273
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	2.30%	1.90%
Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 1,238	$ 2,558
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	2.60%	3.80%
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 6,297	$ 2,176
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	13.30%	3.20%
Commercial & industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 521	$ 0
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	1.10%	0.00%
HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 548	$ 563
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	1.20%	0.80%
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual of interest	$ 0	$ 680
Ratio of nonaccrual loan by portfolio segment to total loans on nonaccrual status	0.00%	1.00%