QUARTERLY RESULTS OF OPERATIONS (unaudited) (Details-Statements of Operations) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$ 257,211	$ 242,148	$ 244,395	$ 231,392	$ 235,552	$ 227,607	$ 230,014	$ 229,013	$ 975,146	$ 922,186	$ 884,535
Total operating expenses	257,755	225,700	228,525	232,280	217,252	216,765	215,853	222,266	944,260	872,136	846,055
Total other expenses	(27,620)	10,670	10,646	10,040	9,889	9,328	8,009	9,993
Equity in earnings of joint ventures	(1,830)	(2,822)	(3,748)	(2,977)	(5,182)	(3,450)	(2,994)	(1,928)	(11,377)	(13,554)	(9,767)
Benefit from (provision for) income taxes	2,441	(2,827)	(2,505)	2,497	(20,133)	(1,112)	(3,523)	458	(394)	(24,310)	(4,432)
Net (loss) income	31,347	5,773	6,467	(5,454)	(6,540)	3,852	5,623	(860)	38,133	2,075	8,004
Net income (loss) attributable to noncontrolling interests	2,211	734	1,061	1,884	736	623	313	350	5,890	2,022	774
Net (loss) income attributable to Radnet, Inc. common stockholders	$ 29,136	$ 5,039	$ 5,406	$ (7,338)	$ (7,276)	$ 3,229	$ 5,310	$ (1,210)	$ 32,243	$ 53	$ 7,230
Basic net (loss) income attributable to Radnet, Inc. common stockholders (loss) earnings per share (in dollars per share)	$ 0.60	$ 0.10	$ 0.11	$ (0.15)	$ (0.15)	$ 0.07	$ 0.11	$ (0.03)	$ 0.67	$ 0.00	$ 0.16
Diluted net (loss) income attributable to Radnet, Inc. common stockholders (loss) earnings per share (in dollars per share)	$ 0.59	$ 0.10	$ 0.11	$ (0.15)	$ (0.15)	$ 0.07	$ 0.11	$ (0.03)	$ 0.66	$ 0.00	$ 0.15
Weighted average shares outstanding, basic (in shares)	48,633	48,011	47,969	47,823	47,237	46,954	46,756	46,560	48,114,275	46,880,775	46,244,188
Weighted average shares outstanding, diluted (in shares)	49,259	48,615	48,526	47,823	47,886	47,578	47,196	46,560	48,678,999	47,401,921	46,655,032