Common and Preferred Stock Investments - Schedule of Common Stock, Preferred Stock, and Warrant Investments at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Schedule of Equity Method Investments [Line Items]
Common stock investments	$ 52,860	$ 49,104
NexPoint Storage Partners
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	42,824	42,824
Common stock investments	$ 24,892	$ 24,761
Private REIT
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	1,394,213	1,394,213
Common stock investments	$ 27,968	$ 24,343
Life Science \| Series D Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	18,949	18,949
Common stock investments	$ 18,616	$ 18,617
Interest rate	15.50%
Life Science \| Series E Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	137,013	137,013
Common stock investments	$ 136,081	$ 136,115
Interest rate	16.50%
Life Science \| Warrant [Member]
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	55,584,966	55,584,966
Common stock investments	$ 136,739	$ 141,186
Self-Storage \| Series G Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Investment owned, balance (in shares)	3,287	3,178
Common stock investments	$ 3,269	$ 3,161
Interest rate	15.00%