Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Consolidated Balance Sheets [Abstract]
Debt securities, available-for-sale, cost (in dollars)	$ 497,251	$ 450,770
Equity securities, available for sale, cost (in dollars)	$ 25,080	$ 25,360
Common stock, par value (in dollars per share)	$ 0.18	$ 0.18
Common stock, authorized shares	33,333,333	33,333,333
Common stock, issued shares	20,872,831	20,872,831
Treasury stock, shares	1,626,863	1,655,306