SIGNIFICANT ACCOUNTING POLICIES (Details - Revenue) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue from External Customer [Line Items]
Revenue	$ 350,044	$ 332,690	$ 1,046,185	$ 981,928
Imaging Center Segment Revenue
Revenue from External Customer [Line Items]
Revenue	349,144	332,194	1,043,129	981,432
Commercial insurance
Revenue from External Customer [Line Items]
Revenue	189,634	185,723	573,259	555,355
Medicare
Revenue from External Customer [Line Items]
Revenue	78,034	73,163	226,827	207,977
Medicaid
Revenue from External Customer [Line Items]
Revenue	9,669	8,707	28,456	26,198
Workers' compensation/personal injury
Revenue from External Customer [Line Items]
Revenue	13,200	11,554	38,785	32,507
Other patient revenue
Revenue from External Customer [Line Items]
Revenue	7,646	4,800	22,334	14,766
Management fee revenue
Revenue from External Customer [Line Items]
Revenue	6,099	5,255	17,199	16,007
Software revenue
Revenue from External Customer [Line Items]
Revenue	3,430	2,068	9,849	7,115
Other
Revenue from External Customer [Line Items]
Revenue	3,431	3,641	12,054	10,058
Revenue under capitation arrangements
Revenue from External Customer [Line Items]
Revenue	38,001	37,283	114,366	111,449
AI Segment Revenue
Revenue from External Customer [Line Items]
Revenue	$ 900	$ 496	$ 3,056	$ 496