DEBT AND OTHER OBLIGATIONS - Non-Recourse Funding Obligations Outstanding (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Outstanding Principal	$ 2,884,040	$ 2,944,940
Carrying value	2,888,329	2,952,822
Golden Gate Captive Insurance Company (Golden Gate)
Debt Instrument [Line Items]
Outstanding Principal	1,883,000	2,014,000
Carrying value	$ 1,883,000	$ 2,014,000
Year-to-Date Weighted- Avg Interest Rate	4.75%	4.75%
Golden Gate II Captive Insurance Company (Golden Gate II)
Debt Instrument [Line Items]
Outstanding Principal	$ 329,949	$ 309,849
Carrying value	$ 273,535	$ 255,132
Year-to-Date Weighted- Avg Interest Rate	4.24%	1.30%
Golden Gate V
Debt Instrument [Line Items]
Outstanding Principal	$ 670,000	$ 620,000
Carrying value	$ 729,454	$ 681,285
Year-to-Date Weighted- Avg Interest Rate	5.12%	5.12%
MONY
Debt Instrument [Line Items]
Outstanding Principal	$ 1,091	$ 1,091
Carrying value	$ 2,340	$ 2,405
Year-to-Date Weighted- Avg Interest Rate	6.19%	6.19%