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DEBT - Components of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Feb. 28, 2019	Dec. 31, 2018	Aug. 14, 2018
Line of Credit Facility
Principal amount	$ 495,824		$ 551,420
Less: Unamortized debt financing costs	(13,094)		(16,272)
Less: Current portion	(69,747)		(66,320)
Long-term debt, net	412,983		468,828
Secured Debt \| $495 Million Credit Facility
Line of Credit Facility
Principal amount	395,724		445,000
Less: Unamortized debt financing costs	(11,642)		(14,423)
Maximum borrowing capacity	495,000	$ 495,000	495,000
Secured Debt \| $108 Million Credit Facility
Line of Credit Facility
Principal amount	100,100		106,420
Less: Unamortized debt financing costs	(1,452)		(1,849)
Maximum borrowing capacity	$ 108,000		$ 108,000	$ 108,000