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DEBT - Components of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Feb. 28, 2019	Aug. 14, 2018
Line of Credit Facility
Principal amount	$ 488,834	$ 495,824
Less: Unamortized debt financing costs	(12,143)	(13,094)
Less: Current portion	(72,962)	(69,747)
Long-term debt, net	403,729	412,983
Secured Debt \| $495 Million Credit Facility
Line of Credit Facility
Principal amount	390,314	395,724
Less: Unamortized debt financing costs	(10,791)	(11,642)
Maximum borrowing capacity	495,000	495,000	$ 495,000	$ 495,000
Secured Debt \| $108 Million Credit Facility
Line of Credit Facility
Principal amount	98,520	100,100
Less: Unamortized debt financing costs	(1,352)	(1,452)
Maximum borrowing capacity	$ 108,000	$ 108,000	$ 108,000		$ 108,000