Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Equity securities, cost	$ 1,406,542	$ 1,310,009
Debt securities, amortized cost	$ 2,706,761	$ 2,778,117
Common stock, shares authorized	22,000,000	22,000,000
Common stock, shares issued	9,117,787	9,300,448
Common stock, shares outstanding	9,117,787	9,300,448
Treasury stock, shares	232,914	351,532