OFFSETTING OF ASSETS AND LIABILITIES - Offsetting of Derivative Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, not subject to a master netting arrangement	$ 375,829	$ 605,075
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	375,829	605,075
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, not subject to a master netting arrangement	70,322	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	99,199	108,830
Net Amount	206,308	254,140
Free-Standing derivatives
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, subject to a master netting arrangement	263,349	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	263,349	468,871
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, subject to a master netting arrangement	70,322	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	99,199	108,830
Net Amount	93,828	117,936
Total derivatives, subject to a master netting arrangement or similar arrangement
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, subject to a master netting arrangement	263,349	468,871
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	263,349	468,871
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, subject to a master netting arrangement	70,322	242,105
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	99,199	108,830
Net Amount	93,828	117,936
Embedded derivative - Modco reinsurance treaties
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, not subject to a master netting arrangement	7,072	1,009
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	7,072	1,009
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, not subject to a master netting arrangement	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	0	0
Net Amount	7,072	1,009
Embedded derivative - GLWB
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, not subject to a master netting arrangement	105,272	134,995
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	105,272	134,995
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, not subject to a master netting arrangement	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	0	0
Net Amount	105,272	134,995
Other
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, not subject to a master netting arrangement	136	200
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	136	200
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, not subject to a master netting arrangement	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	0	0
Net Amount	136	200
Total derivatives, not subject to a master netting arrangement or similar arrangement
Offsetting of Derivative Assets
Gross Amounts of Recognized Assets, not subject to a master netting arrangement	112,480	136,204
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	112,480	136,204
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, not subject to a master netting arrangement	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Received	0	0
Net Amount	$ 112,480	$ 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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