Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 12,488,875	$ 11,963,406
Equity securities, cost	875	14,875
Long-term debt, fair value	$ 1,360,461	$ 1,191,320
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	320,000,000	320,000,000
Common stock, shares issued	100,812,123	105,812,123
Common stock, shares held in treasury	11,310,536	11,576,487