Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investments
Fixed maturity securities, available for sale, amortized cost	$ 6,059,853	$ 5,856,432
Equity securities, available for sale, cost	395,018	275,827
Other investments, cost	$ 0	$ 18,391
SHAREHOLDERS' EQUITY
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	250,000	250,000
Common stock, shares issued	125,423	125,114
Common stock, shares outstanding	100,182	100,928
Treasury stock	25,241	24,186