SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Future Policy Benefit Liabilities (Details) - Successor - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Reinsurance Recoverables [Abstract]
Future policy benefits	$ 4,819,876	$ 5,076,507
Unearned premiums	503,970	460,244
Total policy liabilities and accruals and associated reinsurance receivable	5,323,846	5,536,751
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Future policy benefits	30,511,085	29,703,897
Unearned premiums	848,495	723,536
Total policy liabilities and accruals	31,359,580	30,427,433
Life and Annuity Insurance
Reinsurance Recoverables [Abstract]
Benefit reserves	4,191,845	4,437,387
Future policy benefits	4,515,475	4,760,371
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Benefit reserves	29,574,479	28,767,296
Future policy benefits	30,091,736	29,272,006
Life insurance
Reinsurance Recoverables [Abstract]
Unpaid claim liabilities	323,630	322,984
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Unpaid claim liabilities	517,257	504,710
Other Insurance
Reinsurance Recoverables [Abstract]
Benefit reserves	103,746	115,676
Unpaid claim liabilities	200,655	200,460
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Benefit reserves	170,519	184,719
Unpaid claim liabilities	$ 248,830	$ 247,172