Loans and Allowance for Loan Losses (Details 5) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Summary of loans, by class
Total non-accrual loans	$ 864,036	$ 807,103
Accruing loans delinquent 90 days or more	84,670	64,156
Total non-performing loans	948,706	871,259
One- to four-family, Amortizing [Member]
Summary of loans, by class
Total non-accrual loans	652,081	614,758
Accruing loans delinquent 90 days or more	84,670	64,156
One- to four-family, Interest-only [Member]
Summary of loans, by class
Total non-accrual loans	199,696	179,348
Accruing loans delinquent 90 days or more	0	0
Multi-family and commercial mortgages [Member]
Summary of loans, by class
Total non-accrual loans	525	1,117
Accruing loans delinquent 90 days or more	0	0
Construction loans [Member]
Summary of loans, by class
Total non-accrual loans	6,902	7,560
Accruing loans delinquent 90 days or more	0	0
Fixed-rate second mortgages [Member]
Summary of loans, by class
Total non-accrual loans	567	440
Accruing loans delinquent 90 days or more	0	0
Home equity credit lines [Member]
Summary of loans, by class
Total non-accrual loans	3,644	2,356
Accruing loans delinquent 90 days or more	0	0
Other Loan [Member]
Summary of loans, by class
Total non-accrual loans	621	1,524
Accruing loans delinquent 90 days or more	$ 0	$ 0