Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investments
Fixed maturity securities, available for sale, amortized cost	$ 6,132,246	$ 6,352,737
Equity securities, available for sale, cost	$ 382,550	$ 291,070
SHAREHOLDERS' EQUITY
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	250,000	250,000
Common stock, shares issued	126,837	126,472
Common stock, shares outstanding	95,645	96,521
Treasury stock	31,192	29,951