PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Equipment at cost	$ 13,971	$ 13,984
Total property and equipment cost	1,320,700	1,161,222
Accumulated depreciation	(754,739)	(676,975)
Total property and equipment	565,961	484,247
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	250	250
Medical equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	649,034	560,301
Computer and office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	119,467	144,766
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 501,963	$ 441,921