Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Debt securities, available-for-sale, cost	$ 393,497	$ 383,530
Equity securities, available-for-sale, cost	$ 31,573	$ 32,469
Common stock, par value	$ 0.18	$ 0.18
Common stock, authorized	33,333,333	33,333,333
Common stock, issued	20,872,831	20,872,831
Treasury stock, shares	1,418,003	748,662