LOSS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net loss attributable to American Renal Associates Holdings, Inc.	$ (7,234)	$ (10,479)
Change in the difference between the redemption value and estimated fair value for accounting purposes of the related noncontrolling interests	(258)	(741)
Net loss attributable to common shareholders	$ (7,492)	$ (11,220)
Weighted-average common shares outstanding, basic (in shares)	32,459,792	32,187,715
Weighted-average common shares outstanding, assuming dilution (in shares)	32,459,792	32,187,715
Loss per share, basic and diluted (in USD per share)	$ (0.23)	$ (0.35)
Outstanding options and restricted stock excluded as impact would be anti-dilutive (in shares)	3,469,001	3,573,305