DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 626,705	$ 966,589
Ending balance	624,485	1,143,712
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,631	(509)
Other comprehensive income before reclassifications	1,199	794
Amounts reclassified from accumulated other comprehensive income (loss)	(16)	758
Net current period other comprehensive income	1,183	1,552
Ending balance	2,814	$ 1,043
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amount of derivatives reclassified out of AOCI	$ 551