PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 96,941	$ 100,702
Accumulated depreciation	(55,461)	(54,008)
Net property and equipment	41,480	46,694
Medical equipment and facilities
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	92,132	94,031
Office equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	594	589
Deposits and construction in progress
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,965	3,832
Deposits towards purchase of proton beam systems
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,250	$ 2,250