FAIR VALUE OF FINANCIAL INSTRUMENTS - Reconciliation of Fair Value Measurements for Level 3 (Details) - USD ($)	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2016
Successor
Assets:
Beginning Balance		$ 2,275,504,000	$ 1,826,883,000
Total Realized and Unrealized Gains Included in Earnings		89,223,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		35,574,000
Total Realized and Unrealized Losses Included in Earnings		(84,968,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income		(69,974,000)
Purchases		201,924,000
Sales		(441,594,000)
Transfers in/out of Level 3		(166,570,000)
Other		(12,236,000)
Ending Balance	$ 2,275,504,000	1,826,883,000	1,510,043,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		(3,678,000)
Liabilities:
Beginning Balance		840,409,000	678,068,000
Total Realized and Unrealized Gains Included in Earnings		450,253,000	499,894,000
Total Realized and Unrealized Losses Included in Earnings		(299,835,000)	(489,325,000)
Issuances		368,000	555,000
Settlements		12,291,000	9,844,000
Other			1,249,000
Ending Balance	840,409,000	678,068,000	659,459,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		156,574,000	13,713,000
Transfers
Securities transferred into Level 3			75,700,000.0
Transferred out of Level 3			221,500,000
Transfers from Level 2 to Level 1			12,200,000
Transfers from Level 1 to Level 2			100,000
Successor | Annuity account
Liabilities:
Beginning Balance		98,279,000	92,512,000
Total Realized and Unrealized Losses Included in Earnings		(6,156,000)	(3,144,000)
Issuances		368,000	555,000
Settlements		12,291,000	9,844,000
Other			1,249,000
Ending Balance	98,279,000	92,512,000	87,616,000
Successor | Other liabilities
Liabilities:
Beginning Balance		742,130,000	585,556,000
Total Realized and Unrealized Gains Included in Earnings		450,253,000	499,894,000
Total Realized and Unrealized Losses Included in Earnings		(293,679,000)	(486,181,000)
Ending Balance	742,130,000	585,556,000	571,843,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		156,574,000	13,713,000
Transfers
Transfers from Level 1 to Level 2			120,000,000
Predecessor
Liabilities:
Beginning Balance		1,106,513,000	852,677,000
Total Realized and Unrealized Gains Included in Earnings	61,000
Total Realized and Unrealized Losses Included in Earnings	(254,309,000)
Issuances	7,000
Settlements	419,000
Ending Balance	1,106,513,000	852,677,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	(253,712,000)
Transfers
Securities transferred into Level 3	43,200,000	0
Transferred out of Level 3	0	166,600,000
Transfers from Level 2 to Level 1	0	90,400,000.0
Transfers from Level 1 to Level 2	0	21,000,000
Predecessor | Annuity account
Liabilities:
Beginning Balance		97,949,000	97,825,000
Total Realized and Unrealized Losses Included in Earnings	(536,000)
Issuances	7,000
Settlements	419,000
Ending Balance	97,949,000	97,825,000
Predecessor | Other liabilities
Liabilities:
Beginning Balance		1,008,564,000	754,852,000
Total Realized and Unrealized Gains Included in Earnings	61,000
Total Realized and Unrealized Losses Included in Earnings	(253,773,000)
Ending Balance	1,008,564,000	754,852,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	(253,712,000)
Total investments | Successor
Assets:
Beginning Balance			1,826,883,000
Total Realized and Unrealized Gains Included in Earnings			90,991,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income			83,446,000
Total Realized and Unrealized Losses Included in Earnings			(59,720,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income			(64,574,000)
Purchases			169,403,000
Sales			(379,212,000)
Transfers in/out of Level 3			(145,765,000)
Other			(11,409,000)
Ending Balance		1,826,883,000	1,510,043,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date			28,190,000
Total investments | Predecessor
Assets:
Beginning Balance		2,224,975,000	2,228,475,000
Total Realized and Unrealized Gains Included in Earnings	1,941,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income	12,282,000
Total Realized and Unrealized Losses Included in Earnings	(26,237,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(26,906,000)
Sales	(7,586,000)
Transfers in/out of Level 3	43,205,000
Other	(199,000)
Ending Balance	2,224,975,000	2,228,475,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	(24,296,000)
Residential mortgage-backed securities | Successor | Available-for-sale securities
Assets:
Beginning Balance		3,000	3,000
Ending Balance	3,000	3,000	3,000
Residential mortgage-backed securities | Predecessor | Available-for-sale securities
Assets:
Beginning Balance		3,000	3,000
Ending Balance	3,000	3,000
Commercial mortgage-backed securities | Successor | Available-for-sale securities
Assets:
Total Realized and Unrealized Gains Included in Other Comprehensive Income			7,000
Total Realized and Unrealized Losses Included in Other Comprehensive Income			(1,750,000)
Purchases			25,607,000
Transfers in/out of Level 3			(23,844,000)
Other			(20,000)
Other asset-backed securities | Successor | Available-for-sale securities
Assets:
Beginning Balance		603,646,000	587,031,000
Total Realized and Unrealized Gains Included in Earnings			6,859,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		11,040,000	42,865,000
Total Realized and Unrealized Losses Included in Earnings		(92,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income		(17,076,000)	(29,673,000)
Purchases			30,441,000
Sales		(9,677,000)	(79,314,000)
Transfers in/out of Level 3			7,457,000
Other		(810,000)	(3,062,000)
Ending Balance	603,646,000	587,031,000	562,604,000
Other asset-backed securities | Successor | Trading securities
Assets:
Beginning Balance		169,473,000	152,912,000
Total Realized and Unrealized Gains Included in Earnings		6,260,000	5,386,000
Total Realized and Unrealized Losses Included in Earnings		(7,967,000)	(4,790,000)
Purchases		2,000,000
Sales		(15,154,000)	(70,270,000)
Transfers in/out of Level 3		(1,982,000)	172,000
Other		282,000	1,153,000
Ending Balance	169,473,000	152,912,000	84,563,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		(5,804,000)	594,000
Other asset-backed securities | Predecessor | Available-for-sale securities
Assets:
Beginning Balance		603,646,000	563,961,000
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(3,867,000)
Sales	(32,000)
Transfers in/out of Level 3	43,205,000
Other	379,000
Ending Balance	603,646,000	563,961,000
Other asset-backed securities | Predecessor | Trading securities
Assets:
Beginning Balance		169,473,000	169,461,000
Total Realized and Unrealized Gains Included in Earnings	586,000
Total Realized and Unrealized Losses Included in Earnings	(139,000)
Sales	(472,000)
Other	37,000
Ending Balance	169,473,000	169,461,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	447,000
States, municipals, and political subdivisions | Successor | Available-for-sale securities
Assets:
Beginning Balance		3,675,000
Sales		(3,675,000)
Ending Balance	3,675,000
States, municipals, and political subdivisions | Predecessor | Available-for-sale securities
Assets:
Beginning Balance		3,675,000	3,675,000
Ending Balance	3,675,000	3,675,000
Corporate securities | Successor | Available-for-sale securities
Assets:
Beginning Balance		1,307,259,000	902,119,000
Total Realized and Unrealized Gains Included in Earnings		4,367,000	925,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		24,490,000	40,574,000
Total Realized and Unrealized Losses Included in Earnings		(963,000)	(4,135,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income		(52,898,000)	(33,151,000)
Purchases		199,924,000	102,426,000
Sales		(407,052,000)	(225,557,000)
Transfers in/out of Level 3		(164,588,000)	(109,792,000)
Other		(8,420,000)	(9,363,000)
Ending Balance	1,307,259,000	902,119,000	664,046,000
Corporate securities | Successor | Trading securities
Assets:
Beginning Balance		25,130,000	18,225,000
Total Realized and Unrealized Gains Included in Earnings		501,000	713,000
Total Realized and Unrealized Losses Included in Earnings		(1,407,000)	(442,000)
Purchases			10,906,000
Sales		(5,805,000)	(4,071,000)
Transfers in/out of Level 3			(19,722,000)
Other		(194,000)	(117,000)
Ending Balance	25,130,000	18,225,000	5,492,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		(1,430,000)	101,000
Corporate securities | Predecessor | Available-for-sale securities
Assets:
Beginning Balance		1,307,259,000	1,325,683,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income	12,282,000
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(23,029,000)
Sales	(7,062,000)
Other	(615,000)
Ending Balance	1,307,259,000	1,325,683,000
Corporate securities | Predecessor | Trading securities
Assets:
Beginning Balance		25,130,000	24,744,000
Total Realized and Unrealized Gains Included in Earnings	602,000
Total Realized and Unrealized Losses Included in Earnings	(196,000)
Sales	(20,000)
Ending Balance	25,130,000	24,744,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	406,000
Fixed maturities | Successor
Assets:
Beginning Balance		2,109,186,000	1,660,290,000
Total Realized and Unrealized Gains Included in Earnings		11,128,000	13,883,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		35,530,000	83,446,000
Total Realized and Unrealized Losses Included in Earnings		(10,429,000)	(9,367,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income		(69,974,000)	(64,574,000)
Purchases		201,924,000	169,380,000
Sales		(441,363,000)	(379,212,000)
Transfers in/out of Level 3		(166,570,000)	(145,729,000)
Other		(9,142,000)	(11,409,000)
Ending Balance	2,109,186,000	1,660,290,000	1,316,708,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		(7,234,000)	695,000
Fixed maturities | Successor | Available-for-sale securities
Assets:
Beginning Balance		1,914,583,000	1,489,153,000
Total Realized and Unrealized Gains Included in Earnings		4,367,000	7,784,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		35,530,000	83,446,000
Total Realized and Unrealized Losses Included in Earnings		(1,055,000)	(4,135,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income		(69,974,000)	(64,574,000)
Purchases		199,924,000	158,474,000
Sales		(420,404,000)	(304,871,000)
Transfers in/out of Level 3		(164,588,000)	(126,179,000)
Other		(9,230,000)	(12,445,000)
Ending Balance	1,914,583,000	1,489,153,000	1,226,653,000
Fixed maturities | Successor | Trading securities
Assets:
Beginning Balance		194,603,000	171,137,000
Total Realized and Unrealized Gains Included in Earnings		6,761,000	6,099,000
Total Realized and Unrealized Losses Included in Earnings		(9,374,000)	(5,232,000)
Purchases		2,000,000	10,906,000
Sales		(20,959,000)	(74,341,000)
Transfers in/out of Level 3		(1,982,000)	(19,550,000)
Other		88,000	1,036,000
Ending Balance	194,603,000	171,137,000	90,055,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		(7,234,000)	695,000
Fixed maturities | Predecessor
Assets:
Beginning Balance		2,109,186,000	2,087,527,000
Total Realized and Unrealized Gains Included in Earnings	1,188,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income	12,282,000
Total Realized and Unrealized Losses Included in Earnings	(335,000)
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(26,896,000)
Sales	(7,586,000)
Transfers in/out of Level 3	43,205,000
Other	(199,000)
Ending Balance	2,109,186,000	2,087,527,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	853,000
Fixed maturities | Predecessor | Available-for-sale securities
Assets:
Beginning Balance		1,914,583,000	1,893,322,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income	12,282,000
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(26,896,000)
Sales	(7,094,000)
Transfers in/out of Level 3	43,205,000
Other	(236,000)
Ending Balance	1,914,583,000	1,893,322,000
Fixed maturities | Predecessor | Trading securities
Assets:
Beginning Balance		194,603,000	194,205,000
Total Realized and Unrealized Gains Included in Earnings	1,188,000
Total Realized and Unrealized Losses Included in Earnings	(335,000)
Sales	(492,000)
Other	37,000
Ending Balance	194,603,000	194,205,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	853,000
Equity securities | Successor
Assets:
Beginning Balance		73,044,000	69,763,000
Total Realized and Unrealized Gains Included in Other Comprehensive Income		44,000
Total Realized and Unrealized Losses Included in Earnings			(740,000)
Purchases			23,000
Sales		(231,000)
Transfers in/out of Level 3			(36,000)
Other		(3,094,000)
Ending Balance	73,044,000	69,763,000	69,010,000
Equity securities | Predecessor
Assets:
Beginning Balance		73,044,000	73,054,000
Total Realized and Unrealized Losses Included in Other Comprehensive Income	(10,000)
Ending Balance	73,044,000	73,054,000
Other long-term investments | Successor
Assets:
Beginning Balance		93,274,000	96,830,000
Total Realized and Unrealized Gains Included in Earnings		78,095,000	77,108,000
Total Realized and Unrealized Losses Included in Earnings		(74,539,000)	(49,613,000)
Ending Balance	93,274,000	96,830,000	124,325,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date		3,556,000	27,495,000
Transfers
Transfers from Level 1 to Level 2			169,400,000
Other long-term investments | Predecessor
Assets:
Beginning Balance		42,745,000	$ 67,894,000
Total Realized and Unrealized Gains Included in Earnings	753,000
Total Realized and Unrealized Losses Included in Earnings	(25,902,000)
Ending Balance	42,745,000	$ 67,894,000
Total Gains (losses) included in Earnings related to Instruments still held at the Reporting Date	$ (25,149,000)