EARNINGS PER SHARE - Schedule of Basic Earnings and Diluted Per Share of Common Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator
Net (loss) income	$ (7,896)	$ (289)	$ 4,797	$ (2,177)	$ (3,099)	$ (2,466)
Net income attributable to the member units units before the reorganization	(648)				(648)
Net loss attributable to Greenidge	$ (8,544)				$ (3,747)
Denominator
Basic weighted average shares outstanding	30,116				28,949
Dilutive effect of equity awards	0				0
Dilutive effect of convertible preferred stock	0				0
Diluted weighted average shares outstanding	30,116				28,949
Loss per share
Basic	$ (0.28)				$ (0.13)
Diluted	$ (0.28)				$ (0.13)