Related-Party Transactions - Details of Amounts Due to Related Parties on Our Accompanying Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Related Party Transactions [Abstract]
Base management fee	$ 2,149	$ 2,141
Incentive fee	0	1,589
Other, net	60	80
Total due to Adviser	2,209	3,810
Administration fee	575	536
Cumulative accrued but unpaid portions of prior Administration Fees	242	0
Total due to Administrator	817	536
Total due to Gladstone Securities	8	24
Due to related parties, net	$ 3,034	$ 4,370

Carrying amount as of the balance sheet date of obligations due all related parties.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant