Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Investments
Total fixed maturity securities, Available for sale, Cost or amortized cost	$ 5,819,392	$ 5,856,432
Fair value for equity securities-available for sale, at cost	319,499	275,827
Other investments, cost	$ 1,997	$ 18,391
SHAREHOLDERS' EQUITY
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	250,000	250,000
Common stock, shares issued	125,394	125,114
Common stock, shares outstanding	100,474	100,928
Treasury stock	24,920	24,186