Loans Receivable (excluding Covered Loans) (Loans Receivable, Analysis of Age of Loans in Past Due Status) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	$ 8,144,626	$ 7,714,968
Current	8,029,617	7,563,335
30 Days	25,133	35,179
60 Days	14,411	14,933
90 Days	75,465	101,521
Total	115,009	151,633
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.41%	1.97%
Non-Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	7,864,066	7,365,734
Current	7,752,798	7,224,617
30 Days	24,536	32,437
60 Days	14,053	13,575
90 Days	72,679	95,105
Total	111,268	141,117
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.41%	1.92%
Non-Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	5,464,370	5,356,200
Current	5,367,245	5,237,413
30 Days	18,990	26,888
60 Days	12,878	12,373
90 Days	65,257	79,526
Total	97,125	118,787
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.78%	2.22%
Non-Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	85,412	82,422
Current	84,635	80,047
30 Days	301	0
60 Days	0	0
90 Days	476	2,375
Total	777	2,375
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.91%	2.88%
Non-Acquired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	201,475	130,095
Current	201,288	129,678
30 Days	44	417
60 Days	0	0
90 Days	143	0
Total	187	417
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.09%	0.32%
Non-Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	72,241	71,567
Current	70,183	70,106
30 Days	227	0
60 Days	0	0
90 Days	1,831	1,461
Total	2,058	1,461
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.85%	2.04%
Non-Acquired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	111,860	121,473
Current	108,591	117,076
30 Days	1,220	806
60 Days	170	355
90 Days	1,879	3,236
Total	3,269	4,397
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.92%	3.62%
Non-Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	868,968	790,564
Current	865,518	785,793
30 Days	2,829	0
60 Days	214	0
90 Days	407	4,771
Total	3,450	4,771
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.40%	0.60%
Non-Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	476,863	404,680
Current	474,923	398,114
30 Days	95	2,942
60 Days	0	351
90 Days	1,845	3,273
Total	1,940	6,566
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.41%	1.62%
Non-Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	333,543	249,405
Current	333,430	249,363
30 Days	3	42
60 Days	0	0
90 Days	110	0
Total	113	42
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.03%	0.02%
Non-Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	117,178	112,186
Current	116,188	111,407
30 Days	53	493
60 Days	370	213
90 Days	567	73
Total	990	779
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.84%	0.69%
Non-Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	132,156	47,142
Current	130,797	45,620
30 Days	774	849
60 Days	421	283
90 Days	164	390
Total	1,359	1,522
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.03%	3.23%
Acquired Non-Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	197,223	250,350
Current	194,879	243,718
30 Days	357	441
60 Days	358	894
90 Days	1,629	5,297
Total	2,344	6,632
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.19%	2.65%
Acquired Non-Impaired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	12,014	14,468
Current	11,990	14,343
30 Days	0	82
60 Days	0	0
90 Days	24	43
Total	24	125
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.20%	0.86%
Acquired Non-Impaired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Acquired Non-Impaired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Acquired Non-Impaired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	1,069	1,489
Current	663	1,241
30 Days	0	0
60 Days	0	0
90 Days	406	248
Total	406	248
Ratio of past due loans to total loans, net of charge-offs and LIPs	37.98%	16.66%
Acquired Non-Impaired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	2,651	3,313
Current	2,651	2,987
30 Days	0	125
60 Days	0	100
90 Days	0	101
Total	0	326
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	9.84%
Acquired Non-Impaired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	3,057	3,914
Current	3,057	3,914
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	0.00%
Acquired Non-Impaired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	103,189	133,398
Current	102,421	128,610
30 Days	0	134
60 Days	0	617
90 Days	768	4,037
Total	768	4,788
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.74%	3.59%
Acquired Non-Impaired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	60,348	75,323
Current	60,136	74,992
30 Days	212	10
60 Days	0	153
90 Days	0	168
Total	212	331
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.35%	0.44%
Acquired Non-Impaired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	8,468	10,179
Current	8,335	10,063
30 Days	133	0
60 Days	0	16
90 Days	0	100
Total	133	116
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.57%	1.14%
Acquired Non-Impaired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	6,427	8,266
Current	5,626	7,568
30 Days	12	90
60 Days	358	8
90 Days	431	600
Total	801	698
Ratio of past due loans to total loans, net of charge-offs and LIPs	12.46%	8.44%
Credit Impaired Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	83,337	98,884
Current	81,940	95,000
30 Days	240	2,301
60 Days	0	464
90 Days	1,157	1,119
Total	1,397	3,884
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.68%	3.93%
Credit Impaired Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	326	333
Current	326	333
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	0.00%
Credit Impaired Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Credit Impaired Acquired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Ratio of past due loans to total loans, net of charge-offs and LIPs		0.00%
Credit Impaired Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	1,670	2,393
Current	1,670	1,929
30 Days	0	0
60 Days	0	464
90 Days	0	0
Total	0	464
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	19.39%
Credit Impaired Acquired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Ratio of past due loans to total loans, net of charge-offs and LIPs		0.00%
Credit Impaired Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	0
Current	0	0
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	0	0
Ratio of past due loans to total loans, net of charge-offs and LIPs		0.00%
Credit Impaired Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	66,344	83,116
Current	65,996	80,095
30 Days	0	2,301
60 Days	0	0
90 Days	348	720
Total	348	3,021
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.52%	3.63%
Credit Impaired Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	4,281	1,705
Current	3,863	1,396
30 Days	12	0
60 Days	0	0
90 Days	406	309
Total	418	309
Ratio of past due loans to total loans, net of charge-offs and LIPs	9.76%	18.12%
Credit Impaired Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	10,658	11,266
Current	10,027	11,176
30 Days	228	0
60 Days	0	0
90 Days	403	90
Total	631	90
Ratio of past due loans to total loans, net of charge-offs and LIPs	5.92%	0.80%
Credit Impaired Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	58	71
Current	58	71
30 Days	0	0
60 Days	0	0
90 Days	0	0
Total	$ 0	$ 0
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	0.00%