Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Debt securities, available-for-sale, cost	$ 400,376	$ 380,578
Equity securities, available-for-sale, cost	$ 30,376	$ 30,465
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	1,609,374	1,609,374