Loans Receivable (excluding Covered Loans) (Loans Receivable, Analysis of Age of Loans in Past Due Status) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	$ 7,837,046	$ 7,714,968
Current	7,695,002	7,563,335
30 Days	40,851	35,179
60 Days	11,494	14,933
90 Days	89,699	101,521
Total	142,044	151,633
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.81%	1.97%
Non-Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	7,515,854	7,365,734
Current	7,382,760	7,224,617
30 Days	39,456	32,437
60 Days	11,268	13,575
90 Days	82,370	95,105
Total	133,094	141,117
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.77%	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	5,418,864	5,356,200
Current	5,304,409	5,237,413
30 Days	33,199	26,888
60 Days	10,318	12,373
90 Days	70,938	79,526
Total	114,455	118,787
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.11%	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	87,485	82,422
Current	86,398	80,047
30 Days	37	0
60 Days	92	0
90 Days	958	2,375
Total	1,087	2,375
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.24%	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	154,776	130,095
Current	154,610	129,678
30 Days	166	417
60 Days	0	0
90 Days	0	0
Total	166	417
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.11%	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	66,028	71,567
Current	63,890	70,106
30 Days	1	0
60 Days	119	0
90 Days	2,018	1,461
Total	2,138	1,461
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.24%	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	119,024	121,473
Current	114,493	117,076
30 Days	989	806
60 Days	320	355
90 Days	3,222	3,236
Total	4,531	4,397
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.81%	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	812,635	790,564
Current	810,050	785,793
30 Days	1,031	0
60 Days	0	0
90 Days	1,554	4,771
Total	2,585	4,771
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.32%	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	426,898	404,680
Current	422,781	398,114
30 Days	951	2,942
60 Days	0	351
90 Days	3,166	3,273
Total	4,117	6,566
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.96%	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	274,424	249,405
Current	272,589	249,363
30 Days	1,835	42
60 Days	0	0
90 Days	0	0
Total	1,835	42
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.67%	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	111,577	112,186
Current	110,995	111,407
30 Days	346	493
60 Days	114	213
90 Days	122	73
Total	582	779
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.52%	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	44,143	47,142
Current	42,545	45,620
30 Days	901	849
60 Days	305	283
90 Days	392	390
Total	1,598	1,522
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.62%	3.23%
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	228,773	250,350
Current	222,434	243,718
30 Days	703	441
60 Days	162	894
90 Days	5,474	5,297
Total	6,339	6,632
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.77%	2.65%
Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	13,856	14,468
Current	13,813	14,343
30 Days	0	82
60 Days	0	0
90 Days	43	43
Total	43	125
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.31%	0.86%
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
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
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%
Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	1,206	1,489
Current	1,123	1,241
30 Days	83	0
60 Days	0	0
90 Days	0	248
Total	83	248
Ratio of past due loans to total loans, net of charge-offs and LIPs	6.88%	16.66%
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	3,261	3,313
Current	2,935	2,987
30 Days	0	125
60 Days	0	100
90 Days	326	101
Total	326	326
Ratio of past due loans to total loans, net of charge-offs and LIPs	10.00%	9.84%
Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	3,773	3,914
Current	3,636	3,914
30 Days	137	0
60 Days	0	0
90 Days	0	0
Total	137	0
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.63%	0.00%
Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	116,810	133,398
Current	112,685	128,610
30 Days	44	134
60 Days	0	617
90 Days	4,081	4,037
Total	4,125	4,788
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.53%	3.59%
Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	72,575	75,323
Current	71,903	74,992
30 Days	364	10
60 Days	146	153
90 Days	162	168
Total	672	331
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.93%	0.44%
Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	9,538	10,179
Current	9,263	10,063
30 Days	16	0
60 Days	0	16
90 Days	259	100
Total	275	116
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.88%	1.14%
Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	7,754	8,266
Current	7,076	7,568
30 Days	59	90
60 Days	16	8
90 Days	603	600
Total	678	698
Ratio of past due loans to total loans, net of charge-offs and LIPs	8.74%	8.44%
Credit Impaired Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	92,419	98,884
Current	89,808	95,000
30 Days	692	2,301
60 Days	64	464
90 Days	1,855	1,119
Total	2,611	3,884
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.83%	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	331	333
Current	331	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
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
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%	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	2,224	2,393
Current	1,845	1,929
30 Days	0	0
60 Days	0	464
90 Days	379	0
Total	379	464
Ratio of past due loans to total loans, net of charge-offs and LIPs	17.04%	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%	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%	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	71,826	83,116
Current	70,490	80,095
30 Days	379	2,301
60 Days	64	0
90 Days	893	720
Total	1,336	3,021
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.86%	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	7,140	1,705
Current	6,647	1,396
30 Days	0	0
60 Days	0	0
90 Days	493	309
Total	493	309
Ratio of past due loans to total loans, net of charge-offs and LIPs	6.90%	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	10,834	11,266
Current	10,431	11,176
30 Days	313	0
60 Days	0	0
90 Days	90	90
Total	403	90
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.72%	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	64	71
Current	64	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%