Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities held to maturity
Less Than 12 Months, Fair Value, Held to Maturity	$ 209	$ 210
Less Than 12 Months, Unrealized Losses, Held to Maturity	(3)	(4)
12 Months or Longer, Fair Value, Held to Maturity
12 Months or Longer, Unrealized Losses, Held to Maturity
Total Held-to-maturity securities, Fair Value	209	210
Total, Unrealized Losses, Held to Maturity	(3)	(4)
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities available for sale
Less Than 12 Months, Fair Value, Available for Sale	211,240	12,891
Less Than 12 Months, Unrealized Losses, Available for Sale	(546)	(19)
12 Months or Longer, Fair Value, Available for Sale
12 Months, Unrealized Losses, Available for Sale
Total Available for sale securities, Fair Value	211,240	12,891
Total, Unrealized Losses, Available for Sale	(546)
Fair Value and Unrealized Losses of Securities
Total Mortgage-backed Securities, Less Than 12 Months, Fair Value	211,449	13,101
Total Mortgage-backed Securities, Less Than 12 Months, Unrealized Losses	(549)	(23)
Total Mortgage-backed Securities, 12 Months or Longer, Fair Value
Total Mortgage-backed Securities, 12 Months or Longer, Unrealized Losses
Total Mortgage-backed Securities, Fair Value	211,449	13,101
Total Mortgage-backed Securities, Unrealized Losses	(549)	(23)
GNMA pass-through certificates [Member]
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities available for sale
Less Than 12 Months, Fair Value, Available for Sale	19,490	12,891
Less Than 12 Months, Unrealized Losses, Available for Sale	(71)	(19)
12 Months or Longer, Fair Value, Available for Sale
12 Months, Unrealized Losses, Available for Sale
Total Available for sale securities, Fair Value	19,490	12,891
Total, Unrealized Losses, Available for Sale	(71)	(19)
FNMA pass-through certificates [Member]
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities available for sale
Less Than 12 Months, Fair Value, Available for Sale	140,250
Less Than 12 Months, Unrealized Losses, Available for Sale	(303)
12 Months or Longer, Fair Value, Available for Sale
12 Months, Unrealized Losses, Available for Sale
Total Available for sale securities, Fair Value	140,250
Total, Unrealized Losses, Available for Sale	(303)
FHLMC pass-through certificates [Member]
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities available for sale
Less Than 12 Months, Fair Value, Available for Sale	51,500
Less Than 12 Months, Unrealized Losses, Available for Sale	(172)
12 Months or Longer, Fair Value, Available for Sale
12 Months, Unrealized Losses, Available for Sale
Total Available for sale securities, Fair Value	51,500
Total, Unrealized Losses, Available for Sale	(172)
FNMA pass-through certificates [Member]
Amortized cost and estimated fair market value of investment securities and mortgage-backed securities held to maturity
Less Than 12 Months, Fair Value, Held to Maturity	209	210
Less Than 12 Months, Unrealized Losses, Held to Maturity	(3)	(4)
12 Months or Longer, Fair Value, Held to Maturity
12 Months or Longer, Unrealized Losses, Held to Maturity
Total Held-to-maturity securities, Fair Value	209	210
Total, Unrealized Losses, Held to Maturity	$ (3)	$ (4)

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

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-Paragraph 21

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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