Summary of Significant Accounting Policies - Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Accounting Policies [Abstract]
Net (loss) income	$ (8,539)	$ 106
Less: net (loss) income attributable to non-controlling interest	(248)	306
Net loss attributable to Great Elm Group, Inc.	$ (8,291)	$ (200)
Weighted average shares basic and diluted:
Weighted average shares of common stock outstanding	28,543	25,982
Weighted average shares used in computing loss per share	28,543	25,982
Basic loss per share	$ (0.29)	$ (0.01)
Diluted loss per share	$ (0.29)	$ (0.01)