Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 98,612		$ 94,751
Components of other comprehensive income
Unrealized holding gains (losses), net, arising on available-for-sale fixed maturity investments	181,375		311,298
Unrealized holding gains (losses), net, arising on cash flow hedges	17,155		884
Reclassification adjustment for (gains) losses, net, realized in net income	(30,437)		(22,218)
Net unrealized gains (losses) related to investments	168,093		289,964
Future policy benefits, DAC and VOBA adjustments	(35,129)		(57,248)
Employee benefit plan adjustment	2,603		0
Other comprehensive income before income taxes	135,567		232,716
Income tax expense related to items of other comprehensive income	47,448		81,450
Other comprehensive income (loss)	88,119	[1]	151,266	[1]
Total comprehensive income	186,731		246,017
Non-credit component of impaired losses on fixed maturities available-for-sale	$ (2,543)		$ 1,772

[1] Other comprehensive income includes the non-credit component of impaired gains (losses), net, on fixed maturities available-for-sale in the amounts of $(2,543) and $1,772 for the three months ended March 31, 2015 and 2014, respectively.