Non-Controlling Interests and Preferred Stock of Subsidiaries - Summary of Share Activity for Preferred Stock of Subsidiaries (Details) shares in Thousands	3 Months Ended
	Sep. 30, 2022 shares
Minority Interest [Line Items]
Balance, as of June 30, 2022	73,110
Redemption of Preferred Stock	(407)
Balance, as of September 30, 2022	72,703
Great Elm Healthcare, LLC (HC LLC)
Minority Interest [Line Items]
Balance, as of June 30, 2022	38,100
Redemption of Preferred Stock	(407)
Balance, as of September 30, 2022	37,693
Series A-1 Preferred Stock | Great Elm Healthcare, LLC (HC LLC)
Minority Interest [Line Items]
Balance, as of June 30, 2022	4,090
Redemption of Preferred Stock	(407)
Balance, as of September 30, 2022	3,683
Series A-2 Preferred Stock | Great Elm Healthcare, LLC (HC LLC)
Minority Interest [Line Items]
Balance, as of June 30, 2022	34,010
Balance, as of September 30, 2022	34,010
Forest Preferred Stock | Forest Investments, Inc. (Forest)
Minority Interest [Line Items]
Balance, as of June 30, 2022	35,010
Balance, as of September 30, 2022	35,010