Investments (Net Investment Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 60,341	$ 75,956
Less: investment expenses	(1,801)	(2,063)
Net Investment Income, Total	58,540	73,893
Available For Sale Fixed Maturities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	53,294	67,621
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	0	0
Trading Account Assets [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	32	444
Commercial Mortgage Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	6,128	6,822
Policy Loans [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	114	131
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	82	200
Other Long-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 691	$ 738