DERIVATIVE INSTRUMENTS (Decrease in Reported Notional Amount) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Balance, January 1, 2018	$ 397,153
Balance, December 31, 2018	202,609
Interest derivative instruments and total return swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Balance, January 1, 2018	392,790
Impact from expirations	(55,000)
Impact from terminations	(138,607)
Impact from settlements	(905)
Balance, December 31, 2018	$ 198,278