Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 12,699,242	$ 12,488,875	[1]
Equity securities, cost	776	875	[1]
Long-term debt, fair value	$ 1,161,442	$ 1,360,461	[1]
Preferred stock, par value	$ 1	$ 1	[1]
Preferred stock, shares authorized	5,000,000	5,000,000	[1]
Preferred stock, shares outstanding	0	0	[1]
Common stock, par value	$ 1	$ 1	[1]
Common stock, shares authorized	320,000,000	320,000,000	[1]
Common stock, shares issued	139,218,183	151,218,183	[1]
Common stock, shares held in treasury	8,185,698	16,965,802	[1]

[1] Derived from audited financial statements