BUSINESS COMBINATIONS AND RELATED ACTIVITY (Details - Narrative)							12 Months Ended
	Nov. 01, 2022 USD ($) $ / shares shares	Jun. 15, 2022 USD ($) location	Apr. 01, 2022 USD ($) center location	Jan. 20, 2022 USD ($) $ / shares shares	Sep. 01, 2021 USD ($)	Jan. 01, 2021 USD ($)	Dec. 31, 2022 USD ($) location	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2021
Business Acquisition [Line Items]
Goodwill							$ 677,665,000	$ 513,820,000	$ 472,879,000
Property and equipment, net							565,961,000	484,247,000
Gain (loss) on disposition of property plant equipment							(2,529,000)	(8,319,000)	(1,200,000)
Payments to acquire additional interest in subsidiaries							1,441,000	1,441,000	1,635,000
Investment in joint ventures							57,893,000	42,229,000	34,528,000
Contributions						$ 300,000
Sale to noncontrolling interests, net of taxes							6,623,000	11,610,000
Purchase of intangible assets							0	5,130,000	$ 0
Tarzana Medical Center, LLC
Business Acquisition [Line Items]
Purchase of intangible assets					$ 5,200,000
Additional Paid-in Capital
Business Acquisition [Line Items]
Sale to noncontrolling interests, net of taxes					$ 4,200,000		$ 6,623,000	4,206,000
Frederick County Radiology, LLC
Business Acquisition [Line Items]
Number of centers contributed | center			4
Frederick Health Hospital, Inc. | Frederick County Radiology, LLC
Business Acquisition [Line Items]
Fair value of investment			$ 11,100,000
Simi Valley Imaging Group, LLC
Business Acquisition [Line Items]
Investment in joint ventures						400,000
Simi Adventist
Business Acquisition [Line Items]
Investment in joint ventures						$ 100,000
Frederick County Radiology, LLC
Business Acquisition [Line Items]
Number of location | location			6
Frederick County Radiology, LLC
Business Acquisition [Line Items]
Economic interest			65.00%
Frederick County Radiology, LLC | Additional Paid-in Capital
Business Acquisition [Line Items]
Gain (loss) on disposition of property plant equipment			$ 6,600,000
Frederick County Radiology, LLC | Frederick Health Hospital, Inc.
Business Acquisition [Line Items]
Goodwill			11,000,000
Property and equipment, net			$ 8,400,000
Minority partner ownership percent			35.00%
Frederick County Radiology, LLC | Fixed Assets | Frederick Health Hospital, Inc.
Business Acquisition [Line Items]
Property and equipment, net			$ 5,400,000
Frederick County Radiology, LLC | Medical equipment | Frederick Health Hospital, Inc.
Business Acquisition [Line Items]
Property and equipment, net			$ 3,000,000
Advanced Radiology at Capital Region, LLC
Business Acquisition [Line Items]
Number of location | location		2
Economic interest		51.00%
Payments to acquire additional interest in subsidiaries		$ 5,100
Advanced Radiology at Capital Region, LLC | Dimension Health Corporation
Business Acquisition [Line Items]
Economic interest		49.00%
Total net assets		$ 4,900
Simi Valley Imaging Group, LLC
Business Acquisition [Line Items]
Economic interest						60.00%
Number of locations | location							2
Contributions						$ 300,000
Simi Valley Imaging Group, LLC | Simi Valley Imaging Group, LLC
Business Acquisition [Line Items]
Investment in joint ventures						$ 400,000
Simi Valley Imaging Group, LLC | Simi Adventist
Business Acquisition [Line Items]
Economic interest						40.00%
Investment in joint ventures						$ 100,000
West Valley Imaging Group, LLC | Subsidiaries
Business Acquisition [Line Items]
Noncontrolling interest, percent of ownership sold					24.90%
Proceeds from sale of interest in minority shareholders					$ 13,100,000
Noncontrolling interest, ownership percentage by parent					50.10%					75.00%
Software developed for internal use
Business Acquisition [Line Items]
Amortization period							7 years
Customer Relationships
Business Acquisition [Line Items]
Amortization period							3 years
Trade Names
Business Acquisition [Line Items]
Amortization period							7 years
Measurement Input, Discount Rate | Valuation, Income Approach | Minimum
Business Acquisition [Line Items]
Contingent consideration liability, measurement input							0.15
Measurement Input, Discount Rate | Valuation, Income Approach | Maximum
Business Acquisition [Line Items]
Contingent consideration liability, measurement input							0.17
Heart and Lung Imaging Limited
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	75.00%
Consideration transferred	$ 31,900,000
Common stock issued as consideration	$ 6,800,000
Shares issued (in shares) | shares	359,002
Price per share (dollars per share) | $ / shares	$ 19.06
Consideration transferred	$ 6,300,000
Contingent consideration to guarantee share value issued	$ 10,800,000						$ 11,656,000	0
Business combination, contingent consideration, liability, period	24 months
Business combination, noncontrolling interest	$ 8,000,000
Current assets acquired	600,000
Intangible assets	15,800,000
Liabilities	600,000
Goodwill	16,200,000
Property and equipment	$ 0
Heart and Lung Imaging Limited | Measurement Input, Discount Rate | Valuation, Income Approach
Business Acquisition [Line Items]
Contingent consideration liability, measurement input	0.190
Heart and Lung Imaging Limited | Contingent Milestone Consideration
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued	$ 10,200,000						11,100,000
Heart and Lung Imaging Limited | Cash Holdback
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued	$ 600,000
Aidence
Business Acquisition [Line Items]
Consideration transferred				$ 45,200,000
Shares issued (in shares) | shares	359,002			1,141,234
Consideration transferred				$ 1,800,000
Contingent consideration to guarantee share value issued				11,900,000			$ 11,158,000	0
Current assets acquired				1,000,000
Liabilities				3,200,000
Goodwill				22,900,000
Settlement of loan				1,500,000
Property and equipment				200,000
Intangible assets acquired				27,700,000
Deferred tax liabilities acquired				3,500,000
Aidence | Software developed for internal use
Business Acquisition [Line Items]
Intangible assets acquired				21,100,000
Amortization period							7 years
Aidence | In-process research and development
Business Acquisition [Line Items]
Intangible assets acquired				5,500,000
Aidence | Customer Relationships
Business Acquisition [Line Items]
Amortization period							5 years 4 months 24 days
Aidence | Trade Names
Business Acquisition [Line Items]
Amortization period							7 years
Aidence | Other Sellers
Business Acquisition [Line Items]
Common stock issued as consideration				$ 30,000,000
Shares issued (in shares) | shares				1,117,872
Price per share (dollars per share) | $ / shares				$ 26.80
Aidence | Certain Seller
Business Acquisition [Line Items]
Common stock issued as consideration				$ 600,000
Shares issued (in shares) | shares				23,362
Aidence | Contingent Milestone Consideration
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued				$ 7,400,000			$ 7,200,000
Aidence | Cash Holdback
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued				4,500,000			4,000,000
Quantib
Business Acquisition [Line Items]
Consideration transferred				42,300,000
Common stock issued as consideration				$ 25,900,000
Shares issued (in shares) | shares				965,058
Consideration transferred				$ 11,800,000
Contingent consideration to guarantee share value issued							$ 3,709,000	$ 0
Business combination, contingent consideration, liability, period				18 months
Current assets acquired				$ 2,400,000
Liabilities				700,000
Long-term liabilities assumed				6,700,000
Goodwill				26,400,000
Property and equipment				100,000
Intangible assets acquired				21,300,000
Quantib | Software developed for internal use
Business Acquisition [Line Items]
Intangible assets acquired				19,600,000
Quantib | In-process research and development
Business Acquisition [Line Items]
Intangible assets acquired				$ 700,000
Quantib | Other Sellers
Business Acquisition [Line Items]
Price per share (dollars per share) | $ / shares				$ 26.80
Quantib | Measurement Input, Discount Rate | Valuation, Income Approach | Minimum
Business Acquisition [Line Items]
Contingent consideration liability, measurement input							0.50
Quantib | Measurement Input, Discount Rate | Valuation, Income Approach | Maximum
Business Acquisition [Line Items]
Contingent consideration liability, measurement input							0.55
Quantib | Contingent Milestone Consideration
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued							$ 2,100,000
Quantib | Cash Holdback
Business Acquisition [Line Items]
Contingent consideration to guarantee share value issued				$ 1,600,000			$ 1,600,000
Quantib | Business Acsuition Contingent Consideration
Business Acquisition [Line Items]
Common stock issued as consideration				$ 3,000,000
Shares issued (in shares) | shares				113,303