Investments (Categories Of Net Investment Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	$ 649,466	$ 682,254	$ 674,656
Investment expenses	(23,249)	(25,825)	(24,360)
Net investment income	626,217	656,429	650,296
Fixed maturity securities
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	486,165	522,309	530,144
Equity securities
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	29,957	28,014	27,013
Commercial mortgage loans on real estate
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	72,658	73,959	76,665
Policy loans
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	2,478	2,939	3,426
Short-term investments
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	2,033	1,950	2,156
Cash and cash equivalents
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	18,416	18,556	14,679
Other investments
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Total investment income	$ 37,759	$ 34,527	$ 20,573