Other Comprehensive Income (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassifications out of accumulated other comprehensive income (loss)
Other realized investment gains (losses), net	$ (55,820)	$ 59,265	$ (64,900)	$ 113,059
Net investment income	375,041	299,675	909,006	892,942
Income before income taxes	105,258	119,372	201,912	294,196
Income tax expense (benefit)	33,287	48,797	67,159	107,673
Total reclassification for the period, Net of tax	8,745	17,204	23,081	45,002
Amount reclassified from accumulated other comprehensive income (loss)
Reclassifications out of accumulated other comprehensive income (loss)
Total reclassification for the period, Net of tax	(8,745)		(23,081)
Unrealized gains (losses) arising on fixed maturities, available-for sale
Reclassifications out of accumulated other comprehensive income (loss)
Total reclassification for the period, Net of tax	8,361	16,734	20,131	43,574
Unrealized gains (losses) arising on fixed maturities, available-for sale | Amount reclassified from accumulated other comprehensive income (loss)
Reclassifications out of accumulated other comprehensive income (loss)
Other realized investment gains (losses), net	(12,863)		(30,971)
Income before income taxes	(12,863)		(30,971)
Income tax expense (benefit)	(4,502)		(10,840)
Income from continuing operations	(8,361)		(20,131)
Gains / (losses) on cash flow hedges
Reclassifications out of accumulated other comprehensive income (loss)
Total reclassification for the period, Net of tax	384	470	2,950	1,428
Gains / (losses) on cash flow hedges | Amount reclassified from accumulated other comprehensive income (loss)
Reclassifications out of accumulated other comprehensive income (loss)
Net investment income	(591)		(4,539)
Income before income taxes	(591)		(4,539)
Income tax expense (benefit)	(207)		(1,589)
Income from continuing operations	$ (384)		$ (2,950)