FACILITY ACQUISITIONS, ASSETS HELD FOR SALE AND DISPOSITIONS (Details - Narrative)												1 Months Ended	12 Months Ended
	Aug. 31, 2020 USD ($) Center	Jun. 01, 2020 USD ($) $ / shares shares	Mar. 02, 2020 USD ($)	Jan. 02, 2020 USD ($)	Aug. 01, 2019 USD ($) Center	Apr. 01, 2019 USD ($) Center	Mar. 01, 2019 USD ($) Center	Feb. 28, 2019 USD ($)	Feb. 01, 2019 USD ($)	Jan. 01, 2019 USD ($)	Apr. 12, 2018 USD ($)	Nov. 06, 2014 USD ($)	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Nov. 01, 2020	Jul. 31, 2019	Jan. 01, 2018 USD ($)	Apr. 01, 2017
Business Acquisition [Line Items]
Fixed assets acquired																		$ 15,000,000.0
Goodwill acquired													$ 472,879,000	$ 441,973,000	$ 418,093,000
Common stock - par value (in dollars per share) | $ / shares													$ 0.0001	$ 0.0001
Sale of ownership interest														$ (134,000)
Proceeds from sale of business													$ 0	$ 132,000	$ 0
AZ Tech
Business Acquisition [Line Items]
Number of businesses acquired | Center	8
Consideration transferred	$ 5,500,000
Fixed assets acquired	2,500,000
Right-of-use assets acquired	7,600,000
Other assets acquired	100,000
Operating lease liabilities acquired	7,600,000
Goodwill acquired	$ 2,900,000
MRI at Woodbridge, LLC
Business Acquisition [Line Items]
Consideration transferred			$ 2,600,000
Fixed assets acquired			500,000
Right-of-use assets acquired			1,100,000
Operating lease liabilities acquired			1,100,000
Goodwill acquired			1,800,000
Intangible assets acquired			300,000
Finance lease liabilities acquired			$ 100,000
Olney Open MRI, LLC
Business Acquisition [Line Items]
Consideration transferred				$ 1,800,000
Fixed assets acquired				800,000
Right-of-use assets acquired				1,300,000
Operating lease liabilities acquired				1,300,000
Goodwill acquired				600,000
Intangible assets acquired				$ 300,000
Imaging On Call
Business Acquisition [Line Items]
Proceeds from sale of business		$ 1,000.0
DeepHealth, Inc.
Business Acquisition [Line Items]
Consideration transferred		34,600,000
Goodwill acquired		$ 23,300,000
Shares issued (in shares) | shares		915,132
Common stock - par value (in dollars per share) | $ / shares		$ 16.93
Shares issued after execution (in shares) | shares		91,517
Shares issued after acquisition, term		18 months
Fair value of shares issued after execution		$ 1,500,000
Fair value of replacement awards attributable to pre-combination		2,000,000.0
Contingent consideration, fair value		17,000,000.0
Business acquisition, closing costs		$ 100,000
Contingent consideration, milestone one, shares issued (in shares) | shares		390,789
Contingent consideration, milestone two, shares issued (in shares) | shares		586,184
Contingent consideration, milestone three, shares issued (in shares) | shares		195,393
Current assets acquired		$ 100,000
Deferred tax liabilities acquired		3,500,000
Intangible assets acquired		$ 14,800,000
Garden State Radiology Network LLC
Business Acquisition [Line Items]
Number of businesses acquired | Center					2
Fixed assets acquired					$ 700,000
Right-of-use assets acquired					400,000
Other assets acquired					1,000.0
Operating lease liabilities acquired					400,000
Goodwill acquired					$ 2,000,000.0
Equity interest percentage					51.00%												49.00%
Sale of ownership interest					$ 1,300,000
Assets assumed					3,100,000
Payments to acquire equity method investments												$ 2,200,000
Nulogix, Inc.
Business Acquisition [Line Items]
Fixed assets acquired					200,000
Goodwill acquired					1,300,000
Deferred tax liabilities acquired					300,000
Intangible assets acquired					$ 700,000
Equity interest percentage					75.00%						25.00%						25.00%
Sale of ownership interest					$ (500,000)
Payments to acquire equity method investments					$ 1,500,000						$ 2,000,000.0
Kern Radiology Imaging Systems Inc.
Business Acquisition [Line Items]
Number of businesses acquired | Center						4
Consideration transferred						$ 19,300,000
Fixed assets acquired						10,100,000
Right-of-use assets acquired						9,700,000
Operating lease liabilities acquired						14,500,000
Goodwill acquired						10,500,000
Intangible assets acquired						3,400,000
Other assets acquired						$ 36,000.0
Zilkha Radiology
Business Acquisition [Line Items]
Number of businesses acquired | Center						2
Consideration transferred						$ 4,500,000
Fixed assets acquired						2,200,000
Right-of-use assets acquired						5,100,000
Operating lease liabilities acquired						5,100,000
Goodwill acquired						2,600,000
Intangible assets acquired						100,000
Finance lease liabilities acquired						$ 300,000
Hudson Valley Radiology Associates
Business Acquisition [Line Items]
Consideration transferred								$ 700,000
Goodwill acquired								3,100,000
Intangible assets acquired								300,000
Value of RadNet stock issued in acquisition								6,000,000.0
Equipment acquired								10,000.0
West Valley Imaging Group, LLC
Business Acquisition [Line Items]
Consideration transferred									$ 3,000,000.0
Fixed assets acquired									300,000
Goodwill acquired									2,500,000
Intangible assets acquired									200,000
Other assets acquired									7,000.0
Ventura County Imaging Group, LLC.
Business Acquisition [Line Items]
Equity interest percentage							60.00%
Payments to acquire equity method investments							$ 10,400,000
DeepHealth Inc.
Business Acquisition [Line Items]
Shares issued at execution (in shares) | shares		823,615
Fair value of shares issued at execution		$ 13,900,000
Dignity Health. | Ventura County Imaging Group, LLC.
Business Acquisition [Line Items]
Number of businesses acquired | Center							3
Fixed assets acquired							$ 4,300,000
Equity interest percentage							40.00%
Payments to acquire equity method investments							$ 6,100,000
Payments to acquire equity method investments, Assets							$ 800,000
Equity interest percentage in exchange for assets							5.00%
Payments to acquire equity method investments, cash							$ 5,300,000
Equity interest percentage in exchange for cash							35.00%
Noncompete Agreements | Hudson Valley Radiology Associates
Business Acquisition [Line Items]
Intangible assets acquired								50,000.0
Trade Names | Hudson Valley Radiology Associates
Business Acquisition [Line Items]
Intangible assets acquired								400,000
Primedex Health Systems Inc. and Radiologix | Hudson Valley Radiology Associates
Business Acquisition [Line Items]
Unfavorable lease contracts acquired								$ 2,800,000
West Valley Imaging Group, LLC | West Valley Imaging Group, LLC
Business Acquisition [Line Items]
Payments to acquire equity method investments									$ 800,000
Noncontrolling interest, ownership percentage									25.00%
Arizona Diagnostic Radiology Group LLC | RadNet
Business Acquisition [Line Items]
Equity interest percentage																49.00%
Arizona Diagnostic Radiology Group LLC | CHI National Services Inc.
Business Acquisition [Line Items]
Equity interest percentage																51.00%
Santa Monica Imaging Group | RadNet
Business Acquisition [Line Items]
Equity interest percentage										35.00%									40.00%
Sale of ownership interest										$ (2,000)