Loans Receivable (excluding Covered Loans) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	$ 8,110,309	$ 7,990,545
Ratio of type of loan to total loans receivable	100.00%	100.00%
Allowance for probable losses	118,158	116,741	133,147
Loans in process	273,263	275,577
Discount on acquired loans	31,485	34,143
Deferred net origination fees	35,845	36,054
Charges against loans receivable	458,751	462,515
Loans receivable, net	7,651,558	7,528,030
Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	5,436,083	5,373,950
Ratio of type of loan to total loans receivable	67.00%	67.30%
Allowance for probable losses	67,692	64,184	81,815
Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	135,868	130,778
Ratio of type of loan to total loans receivable	1.70%	1.60%
Allowance for probable losses	8,142	8,407	12,060
Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	333,954	302,722
Ratio of type of loan to total loans receivable	4.10%	3.80%
Allowance for probable losses	1,474	882	347
Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	75,506	81,660
Ratio of type of loan to total loans receivable	0.90%	1.10%
Allowance for probable losses	7,084	9,165	15,598
Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	122,467	124,984
Ratio of type of loan to total loans receivable	1.50%	1.50%
Allowance for probable losses	3,274	3,552	4,937
Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	846,116	835,598
Ratio of type of loan to total loans receivable	10.50%	10.50%
Allowance for probable losses	4,109	3,816	5,280
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	622,240	625,293
Ratio of type of loan to total loans receivable	7.70%	7.90%
Allowance for probable losses	5,868	5,595	1,956
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	354,166	326,450
Ratio of type of loan to total loans receivable	4.40%	4.00%
Allowance for probable losses	16,505	16,614	7,626
HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	131,949	133,631
Ratio of type of loan to total loans receivable	1.60%	1.60%
Allowance for probable losses	943	1,002	965
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	51,960	55,479
Ratio of type of loan to total loans receivable	0.60%	0.70%
Allowance for probable losses	3,067	3,524	2,563
Non-Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	7,788,854	7,641,266
Ratio of type of loan to total loans receivable	96.10%	95.60%
Non-Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	5,421,896	5,359,149
Ratio of type of loan to total loans receivable	66.90%	67.10%
Non-Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	135,868	130,778
Ratio of type of loan to total loans receivable	1.70%	1.60%
Non-Acquired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	333,954	302,722
Ratio of type of loan to total loans receivable	4.10%	3.80%
Non-Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	72,075	77,775
Ratio of type of loan to total loans receivable	0.90%	1.10%
Non-Acquired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	119,206	121,671
Ratio of type of loan to total loans receivable	1.50%	1.50%
Non-Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	842,343	831,684
Ratio of type of loan to total loans receivable	10.40%	10.40%
Non-Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	433,361	414,961
Ratio of type of loan to total loans receivable	5.30%	5.10%
Non-Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	274,432	243,199
Ratio of type of loan to total loans receivable	3.40%	3.00%
Non-Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	111,577	112,186
Ratio of type of loan to total loans receivable	1.40%	1.40%
Non-Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	44,142	47,141
Ratio of type of loan to total loans receivable	0.50%	0.60%
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	229,020	250,379
Ratio of type of loan to total loans receivable	2.80%	3.10%
Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	13,856	14,468
Ratio of type of loan to total loans receivable	0.20%	0.20%
Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0	0
Ratio of type of loan to total loans receivable	0.00%	0.00%
Acquired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0	0
Ratio of type of loan to total loans receivable	0.00%	0.00%
Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	1,206	1,489
Ratio of type of loan to total loans receivable	0.00%	0.00%
Acquired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	3,261	3,313
Ratio of type of loan to total loans receivable	0.00%	0.00%
Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	3,773	3,914
Ratio of type of loan to total loans receivable	0.10%	0.10%
Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	117,038	133,423
Ratio of type of loan to total loans receivable	1.40%	1.70%
Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	72,594	75,326
Ratio of type of loan to total loans receivable	0.90%	0.90%
Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	9,538	10,179
Ratio of type of loan to total loans receivable	0.10%	0.10%
Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	7,754	8,267
Ratio of type of loan to total loans receivable	0.10%	0.10%
Credit Impaired Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	92,435	98,900
Ratio of type of loan to total loans receivable	1.20%	1.30%
Credit Impaired Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	331	333
Ratio of type of loan to total loans receivable	0.00%	0.00%
Credit Impaired Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0	0
Ratio of type of loan to total loans receivable	0.00%	0.00%
Credit Impaired Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	2,225	2,396
Ratio of type of loan to total loans receivable	0.00%	0.00%
Credit Impaired Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0	0
Ratio of type of loan to total loans receivable	0.00%	0.00%
Credit Impaired Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	71,841	76,909
Ratio of type of loan to total loans receivable	1.00%	1.10%
Credit Impaired Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	7,140	7,925
Ratio of type of loan to total loans receivable	0.10%	0.10%
Credit Impaired Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	10,834	11,266
Ratio of type of loan to total loans receivable	0.10%	0.10%
Credit Impaired Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	$ 64	$ 71
Ratio of type of loan to total loans receivable	0.00%	0.00%