OFFSETTING OF ASSETS AND LIABILITIES - Schedule of Derivative Instruments by Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives not subject to a master netting arrangement	$ 636,586	$ 605,075
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	636,586	605,075
Derivative Asset, Not Offset, Policy Election Deduction	270,878	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	68,809	108,830
Net Amount	296,899	254,140
Free-Standing derivatives
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	454,899	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	454,899	468,871
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	270,878	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	68,809	108,830
Net Amount	115,212	117,936
Total derivatives, subject to a master netting arrangement or similar arrangement
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives	454,899	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	454,899	468,871
Derivative Asset, Not Subject to Master Netting Arrangement Deduction	270,878	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	68,809	108,830
Net Amount	115,212	117,936
Embedded derivative - Modco reinsurance treaties
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives not subject to a master netting arrangement	2,650	1,009
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	2,650	1,009
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	0	0
Net Amount	2,650	1,009
Embedded derivative - GLWB
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives not subject to a master netting arrangement	178,896	134,995
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	178,896	134,995
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	0	0
Net Amount	178,896	134,995
Other
Offsetting of Assets
Gross Amounts of Recognized Assets, Derivatives not subject to a master netting arrangement	141	200
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	141	200
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	0	0
Net Amount	141	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	181,687	136,204
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	181,687	136,204
Derivative Asset, Not Offset, Policy Election Deduction	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Cash/Securities Received as Collateral	0	0
Net Amount	$ 181,687	$ 136,204

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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