Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 34,400	$ 40,821	$ 108,837	$ 129,705
Less: investment expenses	(1,290)	(1,428)	(4,082)	(4,353)
Net investment income	33,110	39,393	104,755	125,352
Fixed maturities, available-for-sale
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	28,233	33,864	87,876	108,045
Trading account assets
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	3	1	34	31
Commercial mortgage and other loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	6,120	5,199	16,364	16,601
Policy loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	175	155	563	505
Short-term investments
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	126	64	227	194
Other long-term investments
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ (257)	$ 1,538	$ 3,773	$ 4,329