FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of Level 3 Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Successor
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities	$ 748,821,000	$ 629,555,000
Successor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, assets	553,308,000
Successor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, assets	638,279,000
Successor | Embedded derivative - GLWB
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities	2,400,000,000
Successor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities	115,370,000
Successor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities	147,368,000
Successor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities	$ 46,051,000
Predecessor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, assets		587,031,000
Predecessor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, assets		875,810,000
Predecessor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, assets		181,612,000
Predecessor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities		100,329,000
Predecessor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities		29,629,000
Annuity account | Predecessor | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value, liabilities		$ 92,512,000
Actuarial cash flow model | Successor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Utilization (as a percent)	99.00%
Policies that have a one-time over-utilization rate of a specified amount (as a percent)	10.00%
Actuarial cash flow model | Successor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Expenses per policy	$ 126
Withdrawal rate prior to age 70 (as a percent)	1.00%
Withdrawal rate for ages 70 or more (as a percent)	100.00%
Actuarial cash flow model | Predecessor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Utilization (as a percent)		99.00%
Policies that have a one-time over-utilization rate of a specified amount (as a percent)		10.00%
Actuarial cash flow model | Predecessor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Expenses per policy		$ 81.50
Actuarial cash flow model | Annuity account | Predecessor | Level 3
Assets and liabilities measured at fair value on a recurring basis
Expenses per policy		$ 81
Withdrawal rate (as a percent)		2.20%
Minimum | Embedded derivative - GLWB
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	91.10%
Minimum | Liquidation technique | Successor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidation value	$ 88
Minimum | Discounted Cash Flow | Successor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)	0.31%
Minimum | Discounted Cash Flow | Predecessor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidity premium (as a percent)		0.27%
Paydown rate (as a percent)		10.20%
Minimum | Discounted Cash Flow | Predecessor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)		0.10%
Minimum | Actuarial cash flow model | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	38.00%
Minimum | Actuarial cash flow model | Successor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	91.10%
Fair value inputs, lapse rate	0.30%
Nonperformance risk (as a percent)	0.18%
Minimum | Actuarial cash flow model | Successor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate	2.00%
Nonperformance risk (as a percent)	0.18%
Asset earned rate (as a percent)	4.08%
Minimum | Actuarial cash flow model | Successor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	38.00%
Fair value inputs, lapse rate	0.50%
Nonperformance risk (as a percent)	0.18%
Minimum | Actuarial cash flow model | Predecessor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		0.30%
Nonperformance risk (as a percent)		0.18%
Minimum | Actuarial cash flow model | Predecessor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		2.50%
Nonperformance risk (as a percent)		0.18%
Withdrawal rate (as a percent)		1.10%
Minimum | Actuarial cash flow model | Predecessor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)		38.00%
Fair value inputs, lapse rate		0.50%
Nonperformance risk (as a percent)		0.18%
Minimum | Actuarial cash flow model | Annuity account | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	46.00%
Minimum | Actuarial cash flow model | Annuity account | Predecessor | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		2.20%
Return on assets (as a percent)		1.50%
Nonperformance risk (as a percent)		0.18%
Asset earned rate (as a percent)		4.53%
Maximum | Embedded derivative - GLWB
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	106.60%
Maximum | Liquidation technique | Successor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidation value	$ 97.25
Maximum | Discounted Cash Flow | Successor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)	4.50%
Maximum | Discounted Cash Flow | Predecessor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidity premium (as a percent)		1.49%
Paydown rate (as a percent)		14.72%
Maximum | Discounted Cash Flow | Predecessor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)		19.00%
Maximum | Actuarial cash flow model | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	153.00%
Maximum | Actuarial cash flow model | Successor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	106.60%
Fair value inputs, lapse rate	15.00%
Nonperformance risk (as a percent)	1.09%
Maximum | Actuarial cash flow model | Successor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate	40.00%
Nonperformance risk (as a percent)	1.09%
Asset earned rate (as a percent)	4.66%
Maximum | Actuarial cash flow model | Successor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	153.00%
Fair value inputs, lapse rate	10.00%
Nonperformance risk (as a percent)	1.09%
Maximum | Actuarial cash flow model | Predecessor | Embedded derivative - GLWB | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		15.00%
Nonperformance risk (as a percent)		1.04%
Maximum | Actuarial cash flow model | Predecessor | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		40.00%
Nonperformance risk (as a percent)		1.04%
Withdrawal rate (as a percent)		4.50%
Maximum | Actuarial cash flow model | Predecessor | Embedded derivative—IUL | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)		153.00%
Fair value inputs, lapse rate		10.00%
Nonperformance risk (as a percent)		1.04%
Maximum | Actuarial cash flow model | Annuity account | Embedded derivative—FIA | Level 3
Assets and liabilities measured at fair value on a recurring basis
Mortality (as a percent)	113.00%
Maximum | Actuarial cash flow model | Annuity account | Predecessor | Level 3
Assets and liabilities measured at fair value on a recurring basis
Fair value inputs, lapse rate		33.00%
Return on assets (as a percent)		1.85%
Nonperformance risk (as a percent)		1.04%
Asset earned rate (as a percent)		5.67%
Weighted Average | Liquidation technique | Successor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidation value	$ 95.04
Weighted Average | Discounted Cash Flow | Successor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)	2.04%
Weighted Average | Discounted Cash Flow | Predecessor | Other asset-backed securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Liquidity premium (as a percent)		0.42%
Paydown rate (as a percent)		13.11%
Weighted Average | Discounted Cash Flow | Predecessor | Corporate securities | Level 3
Assets and liabilities measured at fair value on a recurring basis
Spread over treasury (as a percent)		2.61%