Revision to Prior Year Information (Consolidated Statements of Financial Operations and Comprehensive Income) (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended								6 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	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUES
Policy charges and fee income			$ 58,931	$ 526,562					$ 585,493	$ 787,195	$ 2,156,387	$ 2,071,039
TOTAL REVENUES	$ 47,874	$ 231,010	140,925	791,393	$ 662,173	$ 762,424	$ 601,620	$ 833,689	932,318	1,211,202	2,859,906	3,090,284
BENEFITS AND EXPENSES
Policyholders’ benefits			(472,610)	100,730					(371,880)	(260,200)	299,150	353,697
Amortization of deferred policy acquisition costs			(10,342)	639,586					629,245	628,101	659,169	431,812
TOTAL BENEFITS AND EXPENSES	132,262	182,006	(588,114)	1,163,700	337,301	920,714	365,827	738,702	575,586	889,854	2,362,544	2,173,547
INCOME (LOSS) FROM OPERATIONS BEFORE INCOME TAXES	(84,388)	49,004	729,039	(372,307)	324,872	(158,290)	235,793	94,987	356,732	321,348	497,362	916,737
Income tax expense (benefit)			5,055	(44,108)					(39,053)	(73,869)	(10,641)	137,069
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
COMPREHENSIVE INCOME (LOSS)			784,869	(212,872)					571,996	$ 401,387	394,117	901,713
As Previously Reported
REVENUES
Policy charges and fee income			41,848	527,407					569,255		2,159,428	2,074,852
TOTAL REVENUES			123,842	792,238					916,080		2,862,947	3,094,097
BENEFITS AND EXPENSES
Policyholders’ benefits			(430,437)	98,528					(331,909)		291,185	343,714
Amortization of deferred policy acquisition costs			(29,866)	640,552					610,687		662,644	436,169
TOTAL BENEFITS AND EXPENSES			(565,465)	1,162,464					596,999		2,358,054	2,167,921
INCOME (LOSS) FROM OPERATIONS BEFORE INCOME TAXES			689,307	(370,226)					319,081		504,893	926,176
Income tax expense (benefit)			(5,499)	(44,095)					(49,594)		(8,005)	140,373
NET INCOME (LOSS)			694,806	(326,131)					368,675		512,898	785,803
COMPREHENSIVE INCOME (LOSS)			755,691	(210,804)					544,886		399,012	907,848
Revision
REVENUES
Policy charges and fee income			17,083	(845)					16,238		(3,041)	(3,813)
TOTAL REVENUES			17,083	(845)					16,238		(3,041)	(3,813)
BENEFITS AND EXPENSES
Policyholders’ benefits			(42,173)	2,202					(39,971)		7,965	9,983
Amortization of deferred policy acquisition costs			19,524	(966)					18,558		(3,475)	(4,357)
TOTAL BENEFITS AND EXPENSES			(22,649)	1,236					(21,413)		4,490	5,626
INCOME (LOSS) FROM OPERATIONS BEFORE INCOME TAXES			39,732	(2,081)					37,651		(7,531)	(9,439)
Income tax expense (benefit)			10,554	(13)					10,541		(2,636)	(3,304)
NET INCOME (LOSS)			29,178	(2,068)					27,110		(4,895)	(6,135)
COMPREHENSIVE INCOME (LOSS)			$ 29,178	$ (2,068)					$ 27,110		$ (4,895)	$ (6,135)