CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Radnet, Inc. Stockholders' Equity	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2015		46,281,189
Beginning balance, value at Dec. 31, 2015	$ 36,461	$ 4	$ 197,297	$ (153)	$ (164,571)	$ 32,577	$ 3,884
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change due to adoption of ASU 2016-09	7,130				7,130	7,130
Issuance of common stock upon exercise of options/warrants (in shares)		314,448
Issuance of common stock upon exercise of options/warrants	150		150			150
Stock-based compensation	5,767		5,767			5,767
Issuance of restricted stock and other awards (in shares)		937,803
Return of common stock (in shares)		(958,536)
Return of common stock	(5,032)		(5,032)			(5,032)
Purchase of noncontrolling interest	(1,094)		(495)			(495)	(599)
Sale to noncontrolling interests, net of taxes	700		700			700
Distributions paid to noncontrolling interests	(492)						(492)
Change in cumulative foreign currency translation adjustment	(49)			(49)		(49)
Change in fair value of cash flow hedge, net of taxes	508			508		508
Net income	8,004				7,230	7,230	774
Ending balance, value at Dec. 31, 2016	52,053	$ 4	198,387	306	(150,211)	48,486	3,567
Ending balance (in shares) at Dec. 31, 2016		46,574,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		867,248
Stock-based compensation	7,834	$ 1	7,833			7,834
Issuance of stock for acquisitions (in shares)		281,763
Issuance of stock for acquisitions	2,500		2,500			2,500
Sale to noncontrolling interests, net of taxes	3,541		3,541			3,541
Contributions from noncontrolling interests	4,304						4,304
Distributions paid to noncontrolling interests	(1,528)						(1,528)
Change in cumulative foreign currency translation adjustment	26			26		26
Change in fair value of cash flow hedge, net of taxes	(880)			(880)		(880)
Net income	2,075				53	53	2,022
Ending balance, value at Dec. 31, 2017	69,925	$ 5	212,261	(548)	(150,158)	61,560	8,365
Ending balance (in shares) at Dec. 31, 2017		47,723,915
Beginning balance (in shares) at Dec. 31, 2016		46,574,904
Beginning balance, value at Dec. 31, 2016	52,053	$ 4	198,387	306	(150,211)	48,486	3,567
Ending balance, value at Dec. 31, 2018	200,253	$ 5	242,835	2,259	(117,915)	127,184	73,069
Ending balance (in shares) at Dec. 31, 2018		48,977,485
Beginning balance (in shares) at Dec. 31, 2017		47,723,915
Beginning balance, value at Dec. 31, 2017	69,925	$ 5	212,261	(548)	(150,158)	61,560	8,365
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock upon exercise of options (in shares)		10,000
Issuance of stock upon exercise of options	20		20			20
Stock-based compensation (in shares)		713,160
Stock-based compensation	7,719		7,719			7,719
Forfeiture of restricted stock (in shares)		(1,150)
Forfeiture of restricted stock	(7)		(7)			(7)
Purchase of noncontrolling interest	(200)		(43)			(43)	(157)
Issuance of stock for acquisitions (in shares)		531,560
Issuance of stock for acquisitions	8,000		8,000			8,000
Sale to noncontrolling interests, net of taxes	34,657		11,991			11,991	22,666
Special distribution from noncontrolling interest net of taxes	(6,281)		2,894			2,894	(9,175)
Contributions from noncontrolling interests	2,640						2,640
Distributions paid to noncontrolling interests	(1,427)						(1,427)
Re-measurement of noncontrolling interest upon change in control	44,267						44,267
Change in cumulative foreign currency translation adjustment	(69)			(69)		(69)
Change in fair value of cash flow hedge, net of taxes	2,876			2,876		2,876
Net income	38,133				32,243	32,243	5,890
Ending balance, value at Dec. 31, 2018	$ 200,253	$ 5	$ 242,835	$ 2,259	$ (117,915)	$ 127,184	$ 73,069
Ending balance (in shares) at Dec. 31, 2018		48,977,485