DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 626,705	$ 966,589
Ending balance	$ 624,440	$ 646,481	624,440	646,481
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	2,814	1,043	1,631	(509)
Other comprehensive income (loss) before reclassifications	560	(983)	1,759	(189)
Amounts reclassified from accumulated other comprehensive income (loss)	(153)	543	(169)	1,301
Net current period other comprehensive income (loss)	407	(440)	1,590	1,112
Ending balance	$ 3,221	$ 603	3,221	$ 603
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amount of derivatives reclassified out of AOCI			$ 911