Restatement of Previously Issued Condensed Consolidated Financial Statements (Details) (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 investment income	$ 375,041	$ 299,675	$ 909,006	$ 892,942
Other realized investment gains (losses), net	(55,820)	59,265	(64,900)	113,059
Total realized investment gains (losses), net	(55,820)	59,041	(65,395)	112,581
Total revenues	608,965	630,950	1,686,642	1,743,338
Amortization of DAC and VOBA	(211)	15,937	30,091	48,428
Total benefits and expenses, net	503,707	511,578	1,484,730	1,449,142
Income before income taxes	105,258	119,372	201,912	294,196
Income tax expense	33,287	48,797	67,159	107,673
Net income	71,971	70,575	134,753	186,523
As previously reported
Net investment income		292,609		895,530
Other realized investment gains (losses), net		55,349		92,402
Total realized investment gains (losses), net		55,125		91,924
Total revenues		619,968		1,725,269
Amortization of DAC and VOBA		15,872		47,103
Total benefits and expenses, net		511,513		1,447,817
Income before income taxes		108,455		277,452
Income tax expense		45,184		102,139
Net income		63,271		175,313
Accounting for forward settling to be announced (TBA) security transactions | Adjustments
Net investment income		7,066		(2,588)
Other realized investment gains (losses), net		3,916		20,657
Total realized investment gains (losses), net		3,916		20,657
Total revenues		10,982		18,069
Amortization of DAC and VOBA		65		1,325
Total benefits and expenses, net		65		1,325
Income before income taxes		10,917		16,744
Income tax expense		3,613		5,534
Net income		$ 7,304		$ 11,210