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, 2012	Sep. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	$ 7,826,527	$ 7,653,050
Current	7,599,952	7,447,005
30 Days	56,801	41,202
60 Days	31,826	24,199
90 Days	137,948	140,644
Total	226,575	206,045
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.89%	2.69%
Non-Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	7,379,747	7,541,953
Current	7,172,706	7,345,497
30 Days	51,412	39,584
60 Days	29,382	21,560
90 Days	126,247	135,312
Total	207,041	196,456
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.81%	2.60%
Non-Acquired Loans [Member] | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	5,570,390	5,776,002
Current	5,414,979	5,618,261
30 Days	36,484	34,035
60 Days	25,122	16,276
90 Days	93,805	107,430
Total	155,411	157,741
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.79%	2.73%
Non-Acquired Loans [Member] | Construction, Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	86,902	88,849
Current	78,536	85,785
30 Days	1,373	142
60 Days	1,911	190
90 Days	5,082	2,732
Total	8,366	3,064
Ratio of past due loans to total loans, net of charge-offs and LIPs	9.63%	3.45%
Non-Acquired Loans [Member] | Construction, Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	120,382	107,882
Current	120,164	107,215
30 Days	32	128
60 Days	147	0
90 Days	39	539
Total	218	667
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.18%	0.62%
Non-Acquired Loans [Member] | Land, Acquisition and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	106,679	119,192
Current	94,278	106,321
30 Days	557	853
60 Days	231	1,004
90 Days	11,613	11,014
Total	12,401	12,871
Ratio of past due loans to total loans, net of charge-offs and LIPs	11.62%	10.80%
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	136,928	141,772
Current	132,135	134,560
30 Days	776	1,688
60 Days	45	375
90 Days	3,972	5,149
Total	4,793	7,212
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.50%	5.09%
Non-Acquired Loans [Member] | Multi Family Housing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	689,164	676,917
Current	681,849	672,263
30 Days	3,102	718
60 Days	130	67
90 Days	4,083	3,869
Total	7,315	4,654
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.06%	0.69%
Non-Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	326,551	292,261
Current	311,428	284,427
30 Days	7,471	699
60 Days	767	3,153
90 Days	6,885	3,982
Total	15,123	7,834
Ratio of past due loans to total loans, net of charge-offs and LIPs	4.63%	2.68%
Non-Acquired Loans [Member] | Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	171,634	162,802
Current	170,760	162,778
30 Days	223	8
60 Days	636	0
90 Days	15	16
Total	874	24
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.51%	0.01%
Non-Acquired Loans [Member] | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	111,986	112,902
Current	111,473	112,482
30 Days	112	158
60 Days	0	64
90 Days	401	198
Total	513	420
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.46%	0.37%
Non-Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	59,131	63,374
Current	57,104	61,405
30 Days	1,282	1,155
60 Days	393	431
90 Days	352	383
Total	2,027	1,969
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.43%	3.11%
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	343,550
Current	330,600
30 Days	5,338
60 Days	1,722
90 Days	5,890
Total	12,950
Ratio of past due loans to total loans, net of charge-offs and LIPs	3.77%
Acquired Loans [Member] | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	15,495
Current	15,306
30 Days	108
60 Days	26
90 Days	55
Total	189
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.22%
Acquired Loans [Member] | Construction, Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	90
Current	90
30 Days	0
60 Days	0
90 Days	0
Total	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	994
Current	994
30 Days	0
60 Days	0
90 Days	0
Total	0
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
Acquired Loans [Member] | Land, Acquisition and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	3,520
Current	3,520
30 Days	0
60 Days	0
90 Days	0
Total	0
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
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	3,891
Current	3,839
30 Days	0
60 Days	0
90 Days	52
Total	52
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
Acquired Loans [Member] | Multi Family Housing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	9,333
Current	5,659
30 Days	0
60 Days	0
90 Days	3,674
Total	3,674
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%
Acquired Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	178,727
Current	175,712
30 Days	0
60 Days	1,661
90 Days	1,354
Total	3,015
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.69%
Acquired Loans [Member] | Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	106,931
Current	101,134
30 Days	5,130
60 Days	0
90 Days	667
Total	5,797
Ratio of past due loans to total loans, net of charge-offs and LIPs	5.42%
Acquired Loans [Member] | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	13,810
Current	13,706
30 Days	16
60 Days	0
90 Days	88
Total	104
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.75%
Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	10,759
Current	10,640
30 Days	84
60 Days	35
90 Days	0
Total	119
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.11%
Credit Impaired Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	103,230	111,097
Current	96,646	101,508
30 Days	51	1,618
60 Days	722	2,639
90 Days	5,811	5,332
Total	6,584	9,589
Ratio of past due loans to total loans, net of charge-offs and LIPs	6.38%	8.63%
Credit Impaired Acquired Loans [Member] | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	340	342
Current	340	342
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	1,755	1,889
Current	1,755	1,889
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, 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 and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	2,676	3,702
Current	2,612	3,219
30 Days	0	365
60 Days	0	0
90 Days	64	118
Total	64	483
Ratio of past due loans to total loans, net of charge-offs and LIPs	2.39%	13.05%
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 Housing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	0	601
Current	0	0
30 Days	0	601
60 Days	0	0
90 Days	0	0
Total	0	601
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 Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	83,637	87,134
Current	77,474	78,959
30 Days	0	412
60 Days	722	2,549
90 Days	5,441	5,214
Total	6,163	8,175
Ratio of past due loans to total loans, net of charge-offs and LIPs	7.37%	9.38%
Credit Impaired Acquired Loans [Member] | Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	1,883	3,292
Current	1,527	3,054
30 Days	51	238
60 Days	0	0
90 Days	305	0
Total	356	238
Ratio of past due loans to total loans, net of charge-offs and LIPs	18.91%	7.23%
Credit Impaired Acquired Loans [Member] | Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	12,849	14,040
Current	12,849	13,950
30 Days	0	0
60 Days	0	90
90 Days	0	0
Total	0	90
Ratio of past due loans to total loans, net of charge-offs and LIPs	0.00%	0.64%
Credit Impaired Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of Loan, Net of Charge-Offs and LIP	90	97
Current	89	95
30 Days	0	2
60 Days	0	0
90 Days	1	0
Total	$ 1	$ 2
Ratio of past due loans to total loans, net of charge-offs and LIPs	1.11%	2.06%