CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED BALANCE SHEETS
Fixed maturities, amortized cost	$ 26,681,324	$ 26,137,960
Fixed maturities at amortized cost, fair value	319,163
Equity securities, cost	409,376	345,874
Mortgage loans, related to securitizations	765,520	858,139
Investment real estate, accumulated depreciation	1,017	1,547
Accounts and premiums receivable, allowance for uncollectible amounts	4,290	3,899
Property and equipment, accumulated depreciation	105,789	134,924
Preferred Stock, par value (in dollars per share)	$ 1	$ 1
Preferred Stock, shares authorized	4,000,000	4,000,000
Preferred Stock, shares Issued (in shares)	0	0
Common Stock, par value (in dollars per share)	$ 0.50	$ 0.50
Common Stock, shares authorized	160,000,000	160,000,000
Common Stock, shares issued	88,776,960	88,776,960
Treasury stock, shares	10,639,467	7,107,765
Net unrealized gains (losses) on investments, income tax	978,656	589,132
Net unrealized (losses) gains relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, income tax	(2,147)	(18,428)
Accumulated loss - derivatives, income tax	(1,883)	(4,111)
Postretirement benefits liability adjustment, income tax	$ (39,468)	$ (35,970)