Related-Party Transactions - Details of Amounts Due to Related Parties on Our Accompanying Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Related Party Transactions [Abstract]
Base management fee	$ 1,376	$ 1,130
Incentive fee	0	883
Other	39	18
Total due to Adviser	1,415	2,031
Administration fee	347	363
Cumulative accrued but unpaid portion of prior Administration Fees	232	75
Total due to Administrator	579	438
Due to Gladstone Securities	0	15
Total due to related parties	$ 1,994	$ 2,484

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

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