DERIVATIVE FINANCIAL INSTRUMENTS - Realized Investments Gains and Losses (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Jan. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2016	Dec. 31, 2015
Successor
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		$ 43,548	$ 10,566	$ 5,618	$ 75,456
Fair Value, Other long-term investments		640,539			640,539	$ 323,570
Successor | Embedded derivative - GMWB
Notional amount and fair value of the entity's derivative financial instruments
Fair Value, Other long-term investments		23,770			23,770	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		1,850			1,850	1,215
Successor | Derivatives with PLC
Notional amount and fair value of the entity's derivative financial instruments
Fair Value, Other long-term investments		37,300			37,300	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		43,548	10,566	5,618	75,456
Notional Amount, Other long-term investments		10,075,149			10,075,149	8,037,250
Fair Value, Other long-term investments		640,539			640,539	323,570
Notional Amount, Other liabilities		10,571,334			10,571,334	9,380,020
Fair Value, Other Liabilities		783,551			783,551	522,225
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		50,454	(98,025)	(138,192)	144,058
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		2,096	1,664	3,644	(4,246)
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		192	1,469	1,880	(792)
Successor | Derivatives not designated as hedging instruments | Interest rate futures | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		31,266	(14,183)	(14,231)	69,067
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		190,058			190,058	262,485
Fair Value, Other long-term investments		752			752	1,275
Notional Amount, Other liabilities		582,493			582,493	233,412
Fair Value, Other Liabilities		7,461			7,461	2,599
Successor | Derivatives not designated as hedging instruments | Equity futures | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(21,328)	(5,267)	(37,736)	(24,556)
Successor | Derivatives not designated as hedging instruments | Equity futures | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		651	123	307	2,033
Successor | Derivatives not designated as hedging instruments | Equity futures | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		47	9	23	(172)
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		314,256			314,256	226,936
Fair Value, Other long-term investments		15,915			15,915	2,499
Notional Amount, Other liabilities		64,445			64,445	46,692
Fair Value, Other Liabilities		1,805			1,805	1,115
Successor | Derivatives not designated as hedging instruments | Currency futures | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		11,112	(8,709)	(2,572)	4,954
Successor | Derivatives not designated as hedging instruments | Volatility futures | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		0	25	29	0
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		2,725,744			2,725,744	2,198,340
Fair Value, Other long-term investments		269,217			269,217	179,458
Notional Amount, Other liabilities		1,459,533			1,459,533	1,205,204
Fair Value, Other Liabilities		60,551			60,551	22,167
Successor | Derivatives not designated as hedging instruments | Equity options | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(3,232)	(3,550)	(25,324)	13,072
Successor | Derivatives not designated as hedging instruments | Equity options | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		735	1,226	5,601	(4,827)
Successor | Derivatives not designated as hedging instruments | Equity options | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		241	(78)	62	214
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		681			681	3,663
Successor | Derivatives not designated as hedging instruments | Interest rate swaptions | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(749)	2,547	(8,781)	(2,983)
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		255,439			255,439	66,408
Notional Amount, Other liabilities		270,000			270,000	475,000
Fair Value, Other Liabilities		3,215			3,215	16,579
Successor | Derivatives not designated as hedging instruments | Interest rate swaps | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		81,554	(121,167)	(175,958)	207,147
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		891,276			891,276	1,723,081
Fair Value, Other long-term investments		23,770			23,770	49,007
Notional Amount, Other liabilities		2,853,530			2,853,530	1,834,308
Fair Value, Other Liabilities		174,988			174,988	67,528
Successor | Derivatives not designated as hedging instruments | Embedded derivative - GMWB | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(66,019)	45,969	81,839	(132,695)
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		1,492,757			1,492,757	1,149,664
Fair Value, Other Liabilities		129,473			129,473	102,378
Successor | Derivatives not designated as hedging instruments | Funds withheld derivative | Annuity account
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		17,850	6,335	44,571	10,052
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		1,313,404			1,313,404	1,110,790
Fair Value, Other Liabilities		119,997			119,997	100,329
Successor | Derivatives not designated as hedging instruments | Embedded derivative - FIA | FIA
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		710	290	(2,293)	(1,452)
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		77,879			77,879	57,760
Fair Value, Other Liabilities		46,711			46,711	29,629
Successor | Derivatives not designated as hedging instruments | Embedded derivative - IUL | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross		(96)	1,538	1,795	(834)
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		(22,820)	109,131	141,322	(81,175)
Notional Amount, Other long-term investments		64,201			64,201	64,593
Fair Value, Other long-term investments		1,850			1,850	1,215
Notional Amount, Other liabilities		2,457,293			2,457,293	2,473,427
Fair Value, Other Liabilities		239,350			239,350	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		13,681	(3,684)	(3,119)	17,711
Notional Amount, Other long-term investments		2,869,315			2,869,315	1,619,200
Fair Value, Other long-term investments		37,300			37,300	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		(55)	$ 11	$ 83	(100)
Notional Amount, Other long-term investments		298			298	242
Fair Value, Other long-term investments		249			249	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		1,155,001			1,155,001	282,373
Fair Value, Other long-term investments		35,366			35,366	1,537
Notional Amount, Other liabilities		0			0	793,763
Fair Value, Other Liabilities		$ 0			$ 0	$ 1,539
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 | 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 | 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 | 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 | Interest rate futures | Annuity account
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 | Equity futures | Annuity account
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 | Equity futures | FIA
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 | Equity futures | IUL
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 | Currency futures | Annuity account
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 | Volatility futures | FIA
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 | Equity options | Annuity account
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 | Equity options | FIA
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 | Equity options | IUL
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 | Interest rate swaptions | Annuity account
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 | Interest rate swaps | Annuity account
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 | Embedded derivative - GMWB | Annuity account
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 | Funds withheld derivative | Annuity account
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 | Embedded derivative - FIA | 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 | Embedded derivative - IUL | IUL
Notional amount and fair value of the entity's derivative financial instruments
Realized investment gains (losses) - derivatives, gross	(486)
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)