4. EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income (loss) attributable to RadNet, Inc.'s common stockholders	$ 4,451	$ (467)	$ (2,829)	$ 877
BASIC NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO RADNET, INC.'S COMMON STOCKHOLDERS
Weighted average number of common shares outstanding during the period	41,644,606	39,235,863	40,734,083	39,105,522
Basic net income (loss) per share attributable to RadNet, Inc.'s common stockholders	$ 0.11	$ (0.01)	$ (0.07)	$ 0.02
DILUTED NET INCOME (LOSS) PER SHARE ATTRIBUTABLE TO RADNET, INC.'S COMMON STOCKHOLDERS
Weighted average number of common shares outstanding during the period	41,644,606	39,235,863	40,734,083	39,105,522
Add nonvested restricted stock subject only to service vesting	1,001,190			311,419
Add additional shares issuable upon exercise of stock options and warrants	1,387,784			469,199
Weighted average number of common shares used in calculating diluted net income per share	44,033,580	39,235,863	40,734,083	39,886,140
Diluted net income (loss) per share attributable to RadNet, Inc.'s common stockholders	$ 0.10	$ (0.01)	$ (0.07)	$ 0.02