Forest Note and Transactions with JPM - Schedule of Loss Before Income Taxes of Forest As well As Loss Before Income Taxes of Forest Attributable to Great Elm Group, Inc (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Note And Transactions [Line Items]
Loss before income taxes	$ (482)	$ (2,679)	$ (1,442)
Loss before income taxes attributable to Great Elm Group, Inc.	$ (1,726)	$ (1,133)	$ (2,508)