DERIVATIVE FINANCIAL INSTRUMENTS - Realized Investments Gains and Losses (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended
	Jan. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2016	Dec. 31, 2015
Successor
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		$ 532	$ 41,895	$ 47,513	$ 75,988
Fair Value, Other long-term investments		673,817			673,817	$ 323,570
Successor | Embedded derivative - GMWB
Notional amount and fair value of the entity's derivative financial instruments
Fair Value, Other long-term investments		33,675			33,675	49,007
Successor | Embedded derivative - Modco reinsurance treaties
Notional amount and fair value of the entity's derivative financial instruments
Fair Value, Other long-term investments		2,787			2,787	1,215
Successor | Derivatives with PLC
Notional amount and fair value of the entity's derivative financial instruments
Fair Value, Other long-term investments		50,687			50,687	18,161
Successor | Derivatives not designated as hedging instruments
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		532	41,895	47,513	75,988
Notional Amount, Other long-term investments		10,672,953			10,672,953	8,037,250
Fair Value, Other long-term investments		673,817			673,817	323,570
Notional Amount, Other liabilities		11,948,629			11,948,629	9,380,020
Fair Value, Other Liabilities		846,911			846,911	522,225
Successor | Derivatives not designated as hedging instruments | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		45,261			45,261	262,485
Fair Value, Other long-term investments		556			556	1,275
Notional Amount, Other liabilities		862,034			862,034	233,412
Fair Value, Other Liabilities		9,504			9,504	2,599
Successor | Derivatives not designated as hedging instruments | Currency futures
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		321,917			321,917	226,936
Fair Value, Other long-term investments		4,735			4,735	2,499
Notional Amount, Other liabilities		81,768			81,768	46,692
Fair Value, Other Liabilities		447			447	1,115
Successor | Derivatives not designated as hedging instruments | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		3,542,544			3,542,544	2,198,340
Fair Value, Other long-term investments		311,158			311,158	179,458
Notional Amount, Other liabilities		2,202,799			2,202,799	1,205,204
Fair Value, Other Liabilities		110,712			110,712	22,167
Successor | Derivatives not designated as hedging instruments | Interest rate swaptions
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		225,000			225,000	225,000
Fair Value, Other long-term investments		451			451	3,663
Successor | Derivatives not designated as hedging instruments | Interest rate swaps
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		1,640,000			1,640,000	1,435,000
Fair Value, Other long-term investments		267,389			267,389	66,408
Notional Amount, Other liabilities		70,000			70,000	475,000
Fair Value, Other Liabilities		1,658			1,658	16,579
Successor | Derivatives not designated as hedging instruments | Embedded derivative - GMWB
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		1,155,640			1,155,640	1,723,081
Fair Value, Other long-term investments		33,675			33,675	49,007
Notional Amount, Other liabilities		2,670,968			2,670,968	1,834,308
Fair Value, Other Liabilities		162,543			162,543	67,528
Successor | Derivatives not designated as hedging instruments | Funds withheld derivative
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other liabilities		1,625,725			1,625,725	1,149,664
Fair Value, Other Liabilities		112,344			112,344	102,378
Successor | Derivatives not designated as hedging instruments | Embedded derivative - FIA
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other liabilities		1,408,469			1,408,469	1,110,790
Fair Value, Other Liabilities		141,651			141,651	100,329
Successor | Derivatives not designated as hedging instruments | Embedded derivative - IUL
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other liabilities		90,848			90,848	57,760
Fair Value, Other Liabilities		46,348			46,348	29,629
Successor | Derivatives not designated as hedging instruments | Embedded derivative - Modco reinsurance treaties
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(24,187)	(9,817)	131,505	(105,362)
Notional Amount, Other long-term investments		64,411			64,411	64,593
Fair Value, Other long-term investments		2,787			2,787	1,215
Notional Amount, Other liabilities		2,455,121			2,455,121	2,473,427
Fair Value, Other Liabilities		254,285			254,285	178,362
Successor | Derivatives not designated as hedging instruments | Derivatives with PLC
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		13,387	(12,978)	(16,096)	31,098
Notional Amount, Other long-term investments		2,881,274			2,881,274	1,619,200
Fair Value, Other long-term investments		50,687			50,687	18,161
Successor | Derivatives not designated as hedging instruments | Other derivatives
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		49	(50)	33	(51)
Notional Amount, Other long-term investments		212			212	242
Fair Value, Other long-term investments		123			123	347
Successor | Derivatives not designated as hedging instruments | Interest rate futures
Notional amount and fair value of the entity's derivative financial instruments
Notional Amount, Other long-term investments		796,694			796,694	282,373
Fair Value, Other long-term investments		2,256			2,256	1,537
Notional Amount, Other liabilities		480,897			480,897	793,763
Fair Value, Other Liabilities		7,419			7,419	$ 1,539
Successor | Derivatives not designated as hedging instruments | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		8,106	64,632	(73,560)	152,164
Successor | Derivatives not designated as hedging instruments | Annuity account | Interest rate futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(7,002)	12,140	(2,091)	62,065
Successor | Derivatives not designated as hedging instruments | Annuity account | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(41,836)	40,951	3,215	(66,392)
Successor | Derivatives not designated as hedging instruments | Annuity account | Currency futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		934	4,000	1,428	5,888
Successor | Derivatives not designated as hedging instruments | Annuity account | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(36,482)	33,519	8,195	(23,410)
Successor | Derivatives not designated as hedging instruments | Annuity account | Interest rate swaptions
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(229)	(3,618)	(12,399)	(3,212)
Successor | Derivatives not designated as hedging instruments | Annuity account | Interest rate swaps
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		14,737	101,808	(74,150)	221,884
Successor | Derivatives not designated as hedging instruments | Annuity account | Embedded derivative - GMWB
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		24,150	(71,296)	10,543	(108,545)
Successor | Derivatives not designated as hedging instruments | Annuity account | Funds withheld derivative
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		53,834	(52,872)	(8,301)	63,886
Successor | Derivatives not designated as hedging instruments | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(5,667)	(86)	3,558	(9,913)
Successor | Derivatives not designated as hedging instruments | FIA | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		2,236	709	1,016	4,269
Successor | Derivatives not designated as hedging instruments | FIA | Volatility futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		0	(24)	6	0
Successor | Derivatives not designated as hedging instruments | FIA | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		6,583	(12,099)	(6,499)	1,756
Successor | Derivatives not designated as hedging instruments | FIA | Embedded derivative - FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(14,486)	11,328	9,035	(15,938)
Successor | Derivatives not designated as hedging instruments | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		8,844	194	2,073	8,052
Successor | Derivatives not designated as hedging instruments | IUL | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		101	17	39	(71)
Successor | Derivatives not designated as hedging instruments | IUL | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		1,607	(1,110)	(1,048)	1,821
Successor | Derivatives not designated as hedging instruments | IUL | Embedded derivative - IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		$ 7,136	$ 1,287	$ 3,082	$ 6,302
Predecessor
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	$ 22,031
Predecessor | Derivatives not designated as hedging instruments
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	22,031
Predecessor | Derivatives not designated as hedging instruments | Embedded derivative - Modco reinsurance treaties
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(68,026)
Predecessor | Derivatives not designated as hedging instruments | Derivatives with PLC
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	15,863
Predecessor | Derivatives not designated as hedging instruments | Other derivatives
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(37)
Predecessor | Derivatives not designated as hedging instruments | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	75,861
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Interest rate futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	1,413
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	9,221
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Currency futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	7,778
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	3,047
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Interest rate swaptions
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	9,268
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Interest rate swaps
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	122,710
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Embedded derivative - GMWB
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(68,503)
Predecessor | Derivatives not designated as hedging instruments | Annuity account | Funds withheld derivative
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(9,073)
Predecessor | Derivatives not designated as hedging instruments | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(1,032)
Predecessor | Derivatives not designated as hedging instruments | FIA | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(184)
Predecessor | Derivatives not designated as hedging instruments | FIA | Volatility futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	0
Predecessor | Derivatives not designated as hedging instruments | FIA | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(2,617)
Predecessor | Derivatives not designated as hedging instruments | FIA | Embedded derivative - FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	1,769
Predecessor | Derivatives not designated as hedging instruments | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(598)
Predecessor | Derivatives not designated as hedging instruments | IUL | Equity futures
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	3
Predecessor | Derivatives not designated as hedging instruments | IUL | Equity options
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(115)
Predecessor | Derivatives not designated as hedging instruments | IUL | Embedded derivative - IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	$ (486)