Loans Receivable And Allowance For Credit Losses (Recorded Investment In Classified Loans) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	$ 6,141,602	$ 5,967,690
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	23,601	33,293
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	42,568	42,788
One-To Four-Family Loans - Originated [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	5,343,211	5,120,849
One-To Four-Family Loans - Originated [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	21,099	29,359
One-To Four-Family Loans - Originated [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	28,970	27,761
One-To Four-Family Loans - Purchased [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	584,887	648,587
One-To Four-Family Loans - Purchased [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	2,331	1,871
One-To Four-Family Loans - Purchased [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	12,706	14,195
Multi-Family And Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	77,899	57,603
Multi-Family And Commercial Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment		1,976
Consumer - Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	130,645	135,028
Consumer - Home Equity [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	171	87
Consumer - Home Equity [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	868	819
Consumer - Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	4,960	5,623
Consumer - Other [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivable, Total Recorded Investment	$ 24	$ 13