Restatement of Previously Issued Condensed Consolidated Financial Statements (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Net income	$ 71,971		$ 70,575		$ 134,753		$ 186,523
Unrealized (losses) gains arising on fixed maturities, available-for-sale	(20,574)	[1]	281,812	[1]	(650,447)	[1]	488,870	[1]
Reclassification adjustment for losses (gains) realized in net income	(13,454)		(26,467)		(35,510)		(69,234)
Net unrealized losses (gains) related to investments	(83,936)		246,767		(718,957)		418,097
Future policy benefits, DAC, and VOBA adjustments	26,455		(78,023)		162,987		(106,646)
Other comprehensive income (loss) before income taxes			168,744				311,451
Income tax (benefit) expense related to items of other comprehensive income (loss)	(20,117)		59,060		(194,589)		109,008
Other comprehensive income (loss)	(37,364)		109,684		(361,381)		202,443
Comprehensive income (loss)	34,607		180,259		(226,628)		388,966
As previously reported
Net income			63,271				175,313
Unrealized (losses) gains arising on fixed maturities, available-for-sale			300,076				511,810
Reclassification adjustment for losses (gains) realized in net income			(37,801)				(82,482)
Net unrealized losses (gains) related to investments			253,697				427,789
Future policy benefits, DAC, and VOBA adjustments			(79,224)				(108,286)
Other comprehensive income (loss) before income taxes			174,473				319,503
Income tax (benefit) expense related to items of other comprehensive income (loss)			61,066				111,826
Other comprehensive income (loss)			113,407				207,677
Comprehensive income (loss)			176,678				382,990
Accounting for forward settling to be announced (TBA) security transactions | Adjustments
Net income			7,304				11,210
Unrealized (losses) gains arising on fixed maturities, available-for-sale			(18,264)				(22,940)
Reclassification adjustment for losses (gains) realized in net income			11,334				13,248
Net unrealized losses (gains) related to investments			(6,930)				(9,692)
Future policy benefits, DAC, and VOBA adjustments			1,201				1,640
Other comprehensive income (loss) before income taxes			(5,729)				(8,052)
Income tax (benefit) expense related to items of other comprehensive income (loss)			(2,006)				(2,818)
Other comprehensive income (loss)			(3,723)				(5,234)
Comprehensive income (loss)			$ 3,581				$ 5,976

[1] Other comprehensive income (loss) includes the non-credit component of impaired losses on fixed maturities available-for-sale in the amounts of $3,173 and $9,218 for the three months ended September 30, 2013 and 2012, respectively, and $9,818 and $16,151 for the nine months ended September 30, 2013 and 2012, respectively.