CONSOLIDATED QUARTERLY RESULTS - UNAUDITED (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended							11 Months Ended	12 Months Ended
	Jan. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Entity Information [Line Items]
Income before income tax	$ 1,182									$ 399,842	$ 593,997	$ 583,289
Successor
Entity Information [Line Items]
Premiums and policy fees		$ 509,008	$ 862,644	$ 834,544	$ 857,948	$ 852,795	$ 869,213	$ 797,741	$ 832,088	3,008,050	3,407,931
Reinsurance ceded		(141,401)	(345,555)	(322,229)	(336,605)	(310,327)	(361,559)	(306,774)	(345,244)	(1,154,978)	(1,314,716)
Net of reinsurance ceded		367,607	517,089	512,315	521,343	542,468	507,654	490,967	486,844	1,853,072	2,093,215
Net investment income		288,872	496,150	482,729	488,460	475,117	467,165	440,620	436,291	1,632,948	1,942,456
Realized investment gains (losses)		(1,415)	12,457	24,268	5,417	8,229	(69,693)	(79,306)	(13,468)	(163,882)	32,623
Net impairment losses recognized in earnings			(10,856)	(3,308)	(967)	(2,617)				(26,993)	(17,748)
Other income		67,263	102,147	107,642	102,148	103,716	103,862	108,312	109,094	388,531	415,653
Total revenues		722,327	1,116,987	1,123,646	1,116,401	1,126,913	1,008,988	960,593	1,018,761	3,710,669	4,483,947
Total benefits and expenses		629,500	996,572	990,567	947,740	955,071	886,143	873,333	921,851	3,310,827	3,889,950
Income before income tax		92,827	120,415	133,079	168,661	171,842	122,845	87,260	96,910	399,842	593,997
Income tax expense (benefit)		29,966	48,148	39,785	56,541	56,494	41,654	26,853	33,070	131,543	200,968
Net income		$ 62,861	$ 72,267	$ 93,294	$ 112,120	$ 115,348	$ 81,191	$ 60,407	$ 63,840	$ 268,299	$ 393,029
Predecessor
Entity Information [Line Items]
Premiums and policy fees	261,866											3,297,768
Reinsurance ceded	(89,956)											(1,373,597)
Net of reinsurance ceded	171,910											1,924,171
Net investment income	175,180											2,197,724
Realized investment gains (losses)	(42,602)											(148,751)
Net impairment losses recognized in earnings	(481)											(7,275)
Other income	36,421											430,428
Total revenues	340,909											4,403,572
Total benefits and expenses	339,727											3,820,283
Income before income tax	1,182											583,289
Income tax expense (benefit)	(327)											198,414
Net income	$ 1,509											$ 384,875
Net income - basic (in dollars per share)	$ 0.02											$ 4.81
Average shares outstanding - basic (in shares)	80,452,848											80,065,217
Net income - diluted (in dollars per share)	$ 0.02											$ 4.73
Average shares outstanding - diluted (in shares)	81,759,287											81,375,496