DERIVATIVE INSTRUMENTS (Schedule of Derivative Notional Amounts) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	$ 202,609	$ 397,153
Total return swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	18,278	72,290
Basis swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	35,000	100,500
Interest rate caps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	80,000	80,000
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	65,000	140,000
Foreign currency forward exchange
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of derivative instruments	$ 4,331	$ 4,363