DERIVATIVE FINANCIAL INSTRUMENTS - Nature and Accounting Treatment of Derivative Instruments (Details) - Successor - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Notional Amount, Other long-term investments	$ 11,184,348	$ 8,464,570
Fair Value, Other long-term investments	542,243	352,016
Notional Amount, Other liabilities	14,274,589	12,935,706
Fair value, liabilities	748,821	629,555
Embedded derivative - Modco reinsurance treaties
Derivative [Line Items]
Fair Value, Other long-term investments	2,573	1,215
Fair value, liabilities	141,301	178,362
Embedded derivative - GLWB
Derivative [Line Items]
Fair Value, Other long-term investments	121,752	95,614
Fair value, liabilities	237,122	277,236
Embedded derivative—FIA
Derivative [Line Items]
Fair value, liabilities	147,368	100,329
Embedded derivative—IUL
Derivative [Line Items]
Fair value, liabilities	46,051	29,629
Cash flow hedges | Foreign currency swaps
Derivative [Line Items]
Notional Amount, Other long-term investments	117,178	0
Fair Value, Other long-term investments	132	0
Cash flow hedges | Inflation
Derivative [Line Items]
Notional Amount, Other liabilities	0	0
Fair value, liabilities	0	0
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Notional Amount, Other long-term investments	1,135,000	1,435,000
Fair Value, Other long-term investments	71,644	66,408
Notional Amount, Other liabilities	575,000	475,000
Fair value, liabilities	10,208	16,579
Derivatives not designated as hedging instruments | Embedded derivative - Modco reinsurance treaties
Derivative [Line Items]
Notional Amount, Other long-term investments	64,123	64,593
Fair Value, Other long-term investments	2,573	1,215
Notional Amount, Other liabilities	2,450,692	2,473,427
Fair value, liabilities	141,301	178,362
Derivatives not designated as hedging instruments | Embedded derivative - GLWB
Derivative [Line Items]
Notional Amount, Other long-term investments	4,601,633	3,769,601
Fair Value, Other long-term investments	121,752	95,614
Notional Amount, Other liabilities	5,962,044	6,539,658
Fair value, liabilities	237,122	277,236
Derivatives not designated as hedging instruments | Interest rate futures
Derivative [Line Items]
Notional Amount, Other long-term investments	102,587	282,373
Fair Value, Other long-term investments	894	1,537
Derivatives not designated as hedging instruments | Equity futures
Derivative [Line Items]
Notional Amount, Other long-term investments	654,113	262,485
Fair Value, Other long-term investments	5,805	1,275
Notional Amount, Other liabilities	102,667	233,412
Fair value, liabilities	2,907	2,599
Derivatives not designated as hedging instruments | Currency futures
Derivative [Line Items]
Notional Amount, Other long-term investments	340,058	226,936
Fair Value, Other long-term investments	7,883	2,499
Notional Amount, Other liabilities	0	46,692
Fair value, liabilities	0	1,115
Derivatives not designated as hedging instruments | Equity options
Derivative [Line Items]
Notional Amount, Other long-term investments	3,944,444	2,198,340
Fair Value, Other long-term investments	328,908	179,458
Notional Amount, Other liabilities	2,590,160	1,205,204
Fair value, liabilities	157,253	22,167
Derivatives not designated as hedging instruments | Interest rate swaptions
Derivative [Line Items]
Notional Amount, Other long-term investments	225,000	225,000
Fair Value, Other long-term investments	2,503	3,663
Derivatives not designated as hedging instruments | Other derivatives
Derivative [Line Items]
Notional Amount, Other long-term investments	212	242
Fair Value, Other long-term investments	149	347
Derivatives not designated as hedging instruments | Embedded derivative—FIA
Derivative [Line Items]
Notional Amount, Other liabilities	1,496,346	1,110,790
Fair value, liabilities	147,368	100,329
Derivatives not designated as hedging instruments | Embedded derivative—IUL
Derivative [Line Items]
Notional Amount, Other liabilities	103,838	57,760
Fair value, liabilities	46,051	29,629
Derivatives not designated as hedging instruments | Interest rate futures
Derivative [Line Items]
Notional Amount, Other liabilities	993,842	793,763
Fair value, liabilities	$ 6,611	$ 1,539