Loans and Allowance for Loan Losses (Details 5) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012 Contract	Dec. 31, 2011 Contract
Troubled debt restructuring by class
Number of Contracts	182	157
Pre-restructuring Outstanding Recorded Investment	$ 79,972	$ 70,217
Post-restructuring Outstanding Recorded Investment	75,616	66,541
One- to four-family, Amortizing [Member]
Troubled debt restructuring by class
Number of Contracts	168	146
Pre-restructuring Outstanding Recorded Investment	65,048	57,336
Post-restructuring Outstanding Recorded Investment	60,827	53,831
One- to four-family, Interest-only [Member]
Troubled debt restructuring by class
Number of Contracts	12	9
Pre-restructuring Outstanding Recorded Investment	7,013	4,970
Post-restructuring Outstanding Recorded Investment	6,878	4,799
Multi-family and commercial mortgages [Member]
Troubled debt restructuring by class
Number of Contracts	2	2
Pre-restructuring Outstanding Recorded Investment	7,911	7,911
Post-restructuring Outstanding Recorded Investment	$ 7,911	$ 7,911