INCOME TAXES - Effective Income Tax Rate and Components of Income Tax and Deferred Liability (Details) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Deferred income tax liabilities:
Change in valuation allowance, before federal income taxes			$ 1,800
Successor
Effective income tax rate related to continuing operations
Statutory federal income tax rate applied to pre-tax income		35.00%	35.00%
State income taxes		2.00%	0.80%
Investment income not subject to tax		(4.30%)	(2.70%)
Uncertain tax positions		0.20%	(0.30%)
Other		0.00%	1.00%
Effective tax rate (as a percent)		32.90%	33.80%
Current income tax expense:
Federal		$ 5,715	$ (50,638)
State		(4,244)	3,919
Total current		1,471	(46,719)
Deferred income tax expense:
Federal		118,338	240,127
State		11,734	7,560
Total deferred		130,072	247,687
Deferred income tax assets:
Loss and credit carryforwards			453,880
Deferred compensation			209,979
Deferred policy acquisition costs			156,012
Premium on corporate debt			104,839
Net unrealized loss on investments			353,448
Other			44,956
Valuation allowance			(6,007)
Deferred income tax assets			1,317,107
Deferred income tax liabilities:
Premium receivables and policy liabilities			884,255
VOBA and other intangibles			720,750
Invested assets (other than unrealized gains (losses))			1,311,866
Deferred income tax liabilities			2,916,871
Net deferred income tax liability		(997,281)	(1,599,764)
State based operating loss carryforwards, valuation allowance		7,400	9,200
State net operating loss carryforwards			19,800
Predecessor
Effective income tax rate related to continuing operations
Statutory federal income tax rate applied to pre-tax income	35.00%			35.00%
State income taxes	0.80%			0.80%
Investment income not subject to tax	(3.20%)			(3.40%)
Uncertain tax positions	(0.10%)			1.30%
Other	(0.10%)			0.30%
Effective tax rate (as a percent)	32.40%			34.00%
Current income tax expense:
Federal	$ (32,803)			$ 189,105
State	1,685			8,838
Total current	(31,118)			197,943
Deferred income tax expense:
Federal	30,858			1,474
State	(67)			(1,003)
Total deferred	$ 30,791			$ 471
Deferred income tax assets:
Loss and credit carryforwards		34,340
Deferred compensation		241,156
Deferred policy acquisition costs		274,366
Premium on corporate debt		125,296
Net unrealized loss on investments		671,540
Other		81,032
Valuation allowance		(4,804)
Deferred income tax assets		1,422,926
Deferred income tax liabilities:
Premium receivables and policy liabilities		276,919
VOBA and other intangibles		631,935
Invested assets (other than unrealized gains (losses))		1,511,353
Deferred income tax liabilities		2,420,207
Net deferred income tax liability		$ (997,281)
2035 | Successor
Deferred income tax liabilities:
Net operating loss carryforwards			226,600
2031
Deferred income tax liabilities:
Net operating loss carryforwards			1,021,500
Foreign Tax Authority
Deferred income tax liabilities:
Foreign tax credits			$ 5,600