OFFSETTING OF ASSETS AND LIABILITIES - Schedule of Derivative Instruments by Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	$ 550,647	$ 629,537
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	550,647	629,537
Derivative Asset, Not Offset, Policy Election Deduction	182,942	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	74,202	108,830
Net Amount	293,503	278,602
Free-Standing derivatives
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	379,860	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	379,860	468,871
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	182,942	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	74,202	108,830
Net Amount	122,716	117,936
Total derivatives, subject to a master netting arrangement or similar arrangement
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	379,860	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	379,860	468,871
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	182,942	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	74,202	108,830
Net Amount	122,716	117,936
Embedded derivative - Modco reinsurance treaties
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	1,551	1,009
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	1,551	1,009
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	1,551	1,009
Embedded derivative - GLWB
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	76,245	67,879
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	76,245	67,879
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	76,245	67,879
Derivatives with PLC
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	92,798	91,578
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	92,798	91,578
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	92,798	91,578
Other
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	193	200
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	193	200
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	193	200
Total derivatives, not subject to a master netting arrangement or similar arrangement
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives Not Subject to a master netting arrangement	170,787	160,666
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	170,787	160,666
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received	0	0
Net Amount	$ 170,787	$ 160,666

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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