Investment in Securities (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Amortized cost and estimated fair value of debt securities by contractual maturity
Due within one year, Held-to-Maturity, Amortized Cost Basis	$ 14,074	$ 25,741
Due after one year through five years, Held-to-Maturity, Amortized Cost Basis	10,048	17,218
U.S. government sponsored enterprise mortgage-backed securities, Amortized Cost Basis	50,939	46,432
Held-to-Maturity, Amortized Cost Basis	75,061	89,391
Due within one year, Held-to-Maturity, Fair Value	14,211	25,915
Due after one year through five years, Held-to-Maturity, Fair Value	10,351	17,678
U.S. government sponsored enterprise mortgage-backed securities, Fair Value	52,515	47,503
Held-to-Maturity, Fair Value	$ 77,077	$ 91,096