Investment Securities (Securities in continuous unrealized loss position) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Fair Value
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 1,018
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,018
Unrealized Losses
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(2)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	(2)
Government Sponsored Enterprises residential mortgage-backed securities [Member]
Fair Value
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,018
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	1,018
Unrealized Losses
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	(2)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Losses	$ (2)