Investments (Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 60,603	$ 71,186	$ 120,945	$ 147,143
Less: investment expenses	(1,669)	(2,009)	(3,471)	(4,073)
Net Investment Income, Total	58,934	69,177	117,474	143,070
Available For Sale Fixed Maturities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	49,240	63,357	102,534	130,979
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	0	7	0	7
Trading Account Assets [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	29	370	61	814
Commercial Mortgage Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	10,274	6,892	16,403	13,714
Policy Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	225	220	339	351
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	96	163	179	363
Other Long-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 739	$ 177	$ 1,429	$ 915