Revision to Prior Year Information (Consolidated Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (85,465)	$ 84,897	$ 723,984	$ (328,199)	$ 348,194	$ (136,506)	$ 214,381	$ 81,934	$ 395,785		$ 395,217	$ 508,003	$ 779,668
Policy charges and fee income				(5,005)					62,525	$ 87,591	113,501	(8,770)	(72,375)
Future policy benefits				424,904					504,822		1,816,665	1,534,228	1,440,542
Reinsurance recoverables				(359,878)					(325,559)	(1,308,146)	(1,764,242)	(1,559,165)	(1,330,796)
Deferred policy acquisition costs				488,313					426,713		311,273	43,168	(194,907)
Income taxes				(125,578)					(67,990)		(45,147)	(36,879)	65,900
Other, net									(260,195)	(191,566)	(110,850)	76,374	26,716
Cash flows from (used in) operating activities				333,424					(186,450)	(209,869)	(6,919)	1,142,929	1,077,692
Proceeds from the sale/maturity/prepayment of:
Fixed maturities, available-for-sale									838,298	970,834	1,371,000	813,721	907,665
Cash flows from (used in) investing activities									(497,625)	(755,911)	(1,101,442)	(838,054)	(853,544)
CASH FLOWS FROM FINANCING ACTIVITIES:
Policyholders’ account deposits										3,125,848	4,289,697	3,839,784	2,966,388
Ceded policyholders’ account deposits									(1,123,608)	(1,688,037)	(2,430,570)	(1,109,311)	(672,242)
Ceded policyholders’ account withdrawals									522,712	745,624	1,072,151	50,016	46,690
Contributed capital									405,321	405,321	405,321	0	0
Cash flows from (used in) financing activities									640,601	674,271	$ 834,232	(149,541)	(316,439)
As Previously Reported
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)			694,806	(326,131)					368,675			512,898	785,803
Policy charges and fee income				(5,850)					78,763	103,829		(11,811)	(76,188)
Future policy benefits				416,396					659,730			1,503,445	1,402,458
Reinsurance recoverables				(353,572)					(326,993)	(1,369,986)		(1,536,347)	(1,302,695)
Deferred policy acquisition costs				489,279					408,155			46,643	(190,550)
Income taxes				(125,565)					(78,531)			(34,243)	69,204
Other, net									(181,862)	19,979
Cash flows from (used in) operating activities				333,424					5,386	(43,926)		1,142,929	1,077,692
Proceeds from the sale/maturity/prepayment of:
Fixed maturities, available-for-sale									798,298	930,834
Cash flows from (used in) investing activities									(537,625)	(795,911)
CASH FLOWS FROM FINANCING ACTIVITIES:
Policyholders’ account deposits										3,085,729
Ceded policyholders’ account deposits									(584,464)	(877,874)
Ceded policyholders’ account withdrawals									32,053	49,958
Contributed capital									205,000	205,000
Cash flows from (used in) financing activities									488,765	548,328
Revision
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)			$ 29,178	(2,068)					27,110			(4,895)	(6,135)
Policy charges and fee income				845					(16,238)	(16,238)		3,041	3,813
Future policy benefits				8,508					(154,908)			30,783	38,084
Reinsurance recoverables				(6,306)					1,434	61,840		(22,818)	(28,101)
Deferred policy acquisition costs				(966)					18,558			(3,475)	(4,357)
Income taxes				(13)					10,541			(2,636)	(3,304)
Other, net									(78,333)	(211,545)
Cash flows from (used in) operating activities				$ 0					(191,836)	(165,943)		$ 0	$ 0
Proceeds from the sale/maturity/prepayment of:
Fixed maturities, available-for-sale									40,000	40,000
Cash flows from (used in) investing activities									40,000	40,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Policyholders’ account deposits										40,119
Ceded policyholders’ account deposits									(539,144)	(810,163)
Ceded policyholders’ account withdrawals									490,659	695,666
Contributed capital									200,321	200,321
Cash flows from (used in) financing activities									$ 151,836	$ 125,943