Investments (Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 71,186	$ 78,314	$ 147,143	$ 161,165
Less: investment expenses	(2,009)	(1,727)	(4,073)	(3,447)
Net Investment Income, Total	69,177	76,587	143,070	157,718
Available For Sale Fixed Maturities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	63,357	69,750	130,979	142,720
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	7	263	7	458
Trading Account Assets [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	370	411	814	1,112
Commercial Mortgage Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	6,892	6,835	13,714	15,144
Policy Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	220	295	351	406
Short-term Investments and cash equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	163	193	363	313
Other Long-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 177	$ 567	$ 915	$ 1,012