The amortized cost of investment securities and their estimated fair value (Details) (in thousands) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Amortized Cost
Obligations of U.S. government sponsored agencies	$ 19,669
Available-for-Sale:
Obligations of U.S. government sponsored agencies	19,669
Obligations of state and political subdivisions	4,427
Government sponsored agency mortgage-backed securities	244,364
Corporate debt securities	6,000
Equity securities	3,000
Total available-for-sale	277,460
Held-to-Maturity:
Government sponsored agency mortgage-backed securities (1)	2	2
Available-for-Sale (1)
Obligations of U.S. government sponsored agencies (1)		19,669
Obligations of state and political subdivisions (1)		5,216
Corporate debt securities (1)		6,000
Equity securities (1)		3,000
Total available-for-sale (1)		285,808
Gross Unrealized Gains
Available-for-Sale:
Obligations of state and political subdivisions	134
Government sponsored agency mortgage-backed securities	2,862
Total available-for-sale	2,996
Held-to-Maturity:
Government sponsored agency mortgage-backed securities (1)		2,528
Available-for-Sale (1)
Obligations of state and political subdivisions (1)		151
Total available-for-sale (1)		2,679
Gross Unrealized Losses
Obligations of U.S. government sponsored agencies	(1,132)
Available-for-Sale:
Obligations of U.S. government sponsored agencies	(1,132)
Obligations of state and political subdivisions	(18)
Government sponsored agency mortgage-backed securities	(4,972)
Corporate debt securities	(1,140)
Equity securities	(51)
Total available-for-sale	(7,313)
Held-to-Maturity:
Government sponsored agency mortgage-backed securities (1)		(6,174)
Available-for-Sale (1)
Obligations of U.S. government sponsored agencies (1)		(1,471)
Obligations of state and political subdivisions (1)		(50)
Corporate debt securities (1)		(1,245)
Equity securities (1)		(68)
Total available-for-sale (1)		(9,008)
Estimated Fair Value
Obligations of U.S. government sponsored agencies	18,537
Available-for-Sale:
Obligations of U.S. government sponsored agencies	18,537
Obligations of state and political subdivisions	4,543
Government sponsored agency mortgage-backed securities	242,254
Corporate debt securities	4,860
Equity securities	2,949
Total available-for-sale	273,143
Held-to-Maturity:
Government sponsored agency mortgage-backed securities (1)	2	2
Available-for-Sale (1)
Obligations of U.S. government sponsored agencies (1)		18,198
Obligations of state and political subdivisions (1)		5,317
Corporate debt securities (1)		4,755
Equity securities (1)		2,932
Total available-for-sale (1)		$ 279,479