Allowance for Losses on Loans (Credit Risk Profile Based on Payment Activity) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	$ 8,031,093	$ 7,866,336
Nonaccrual loans by portfolio segment	163,116	173,427	185,783
Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	7,421,176	7,581,792
Grade as percentage of total gross loans	97.80%	97.80%
Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	264,219		343,665
Grade as percentage of total gross loans	2.02%		2.52%
Nonaccrual loans by portfolio segment	163,116	173,427
Grade as a percetage of total gross loans	2.20%	2.20%
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	5,589,425	5,779,264
Nonaccrual loans by portfolio segment	108,570	131,193
Residential Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	5,465,020	5,647,729
Grade as percentage of total gross loans	98.10%	97.70%
Residential Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	108,570	131,193
Grade as a percetage of total gross loans	1.90%	2.30%
Construction, Speculative [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	125,716	131,526
Nonaccrual loans by portfolio segment	9,471	10,634
Construction, Speculative [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	114,400	119,003
Grade as percentage of total gross loans	92.40%	91.80%
Construction, Speculative [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	9,471	10,634
Grade as a percetage of total gross loans	7.60%	8.20%
Construction, Custom [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	229,134	211,690
Nonaccrual loans by portfolio segment	39	539
Construction, Custom [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	228,101	211,151
Grade as percentage of total gross loans	100.00%	99.70%
Construction, Custom [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	39	539
Grade as a percetage of total gross loans	0.00%	0.30%
Land, Acquisition and Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	115,655	128,379
Nonaccrual loans by portfolio segment	14,318	13,477
Land, Acquisition and Development [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	95,140	111,200
Grade as percentage of total gross loans	86.90%	89.20%
Land, Acquisition and Development [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	14,318	13,477
Grade as a percetage of total gross loans	13.10%	10.80%
Land, Consumer Lot Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	140,997	141,844
Nonaccrual loans by portfolio segment	4,024	5,149
Land, Consumer Lot Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	133,082	136,695
Grade as percentage of total gross loans	97.10%	96.40%
Land, Consumer Lot Loans [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	4,024	5,149
Grade as a percetage of total gross loans	2.90%	3.60%
Multi Family Housing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	731,135	710,741
Nonaccrual loans by portfolio segment	7,907	4,185
Multi Family Housing [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	713,895	705,955
Grade as percentage of total gross loans	98.90%	99.40%
Multi Family Housing [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	7,907	4,185
Grade as a percetage of total gross loans	1.10%	0.60%
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	609,948	406,364
Nonaccrual loans by portfolio segment	16,958	7,653
Commercial Real Estate Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	330,606	311,557
Grade as percentage of total gross loans	95.10%	97.60%
Commercial Real Estate Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	16,958	7,653
Grade as a percetage of total gross loans	4.90%	2.40%
Commercial and Industrial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	280,458	166,115
Nonaccrual loans by portfolio segment	987	16
Commercial and Industrial Loans [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	170,657	162,807
Grade as percentage of total gross loans	99.40%	100.00%
Commercial and Industrial Loans [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	987	16
Grade as a percetage of total gross loans	0.60%	0.00%
Home Equity Line of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	138,645	126,942
Nonaccrual loans by portfolio segment	489	198
Home Equity Line of Credit [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	111,497	112,704
Grade as percentage of total gross loans	99.60%	99.80%
Home Equity Line of Credit [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	489	198
Grade as a percetage of total gross loans	0.40%	0.20%
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	69,980	63,471
Nonaccrual loans by portfolio segment	353	383
Consumer Portfolio Segment [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable, gross	58,778	62,991
Grade as percentage of total gross loans	99.40%	99.40%
Consumer Portfolio Segment [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans by portfolio segment	$ 353	$ 383
Grade as a percetage of total gross loans	0.60%	0.60%