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Related-Party Transactions (Details) |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jul. 11, 2023 | Jul. 14, 2020 | Feb. 20, 2020 $ / shares shares | Feb. 29, 2020 | Dec. 31, 2023 USD ($) quarter officer | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of executive officers | officer |  |  |  |  |  | 2 |  |
Related Party |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Amount due to advisor and administrator | [1] |  |  |  |  | $ 2,556,000 | $ 3,356,000 |
Advisory Agreement |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Number of quarters used for the cap of average quarterly incentive fees | quarter |  |  |  |  |  | 4 |  |
Advisory Agreement | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Notice period for termination of agreement without cause |  |  |  |  |  | 120 days |  |
Percentage of independent directors required to terminate the amended advisory agreement |  |  |  |  |  | 66.67% |  |
Number of times the sum of the average annual base management fee and incentive fee earned by adviser |  |  |  |  |  | 2 |  |
Period prior to termination |  |  |  |  |  | 24 months |  |
Notice period for termination of agreement with cause |  |  |  |  |  | 30 days |  |
Advisory Agreement - Base Rate, Annualized Rate | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, base rate |  |  | 0.425% |  |  |  |  |
Advisory Agreement - Base Rate, Quarterly Rate | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, base rate |  |  | 0.10625% |  |  |  |  |
Advisory Agreement - Base Management Fee |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  | $ 6,400,000 | 6,300,000 | $ 5,900,000
Advisory Agreement - Incentive Rate, Quarterly Hurdle Rate | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  |  |  |  |  | 2.00% |  |
Advisory Agreement - Incentive Rate, Annualized Hurdle Rate | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  |  |  |  |  | 8.00% |  |
Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Below Catch-Up Threshold | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  |  |  |  |  | 15.00% |  |
Advisory Agreement - Incentive Rate, Pre-Incentive Fee Net Investment Income Exceeds Catch-Up Threshold | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  |  |  |  |  | 15.00% |  |
Eight Amended Advisory Agreement | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  | 15.00% |  |  |  |  |  |
Advisory Agreement - Incentive Fees | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  |  | 5,300,000 | 4,900,000
Contractual fee waived |  |  |  |  |  | $ 4,600,000 |  |
Investment company, voluntary fee waived |  |  |  |  |  |  | 0 | 20,000.00
Advisory Agreement - Incentive Rate, Realized Capital Gains |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  | $ 0 | 0 | 0
Advisory Agreement - Incentive Rate, Realized Capital Gains | Affiliated Entity |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Management and service fees, incentive rate |  |  |  |  |  | 15.00% |  |
Administrative Agreement - Administrative Fee |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  | $ 2,400,000 | 1,900,000 | 1,400,000
Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  | $ 100,000 | $ 300,000 | $ 100,000
Mortgage Financing Arrangement Agreement - Percentage of Mortgage Principal Secured | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, rate |  |  |  |  |  | 0.29% | 0.33% | 0.33%
Dealer Manager Agreement | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, amounts of transaction |  |  |  |  |  | $ 500,000 | $ 500,000 | $ 700,000
Dealer Manager Agreement - Selling Commission Percentage of Gross Proceeds From Sales |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, rate |  |  |  | 6.00% |  |  |  |
Dealer Manager Agreement - Dealer Management Fee Percentage of Gross Proceeds from Sale of Preferred Stock in Primary Offering |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, rate |  |  |  | 3.00% |  |  |  |
Series F Cumulative Redeemable Preferred Stock | Preferred Stock | Dealer Manager Agreement | Affiliated Entity | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Redeemable preferred stock, shares authorized (in shares) | shares |  |  |  | 20,000,000 |  |  |  |
Preferred stock, dividend rate |  |  |  |  | 6.00% |  |  |
Redeemable preferred stock, par value (in dollars per share) | $ / shares |  |  |  | $ 0.001 |  |  |  |
Redeemable preferred stock, dividend reinvestment plan, shares authorized (in shares) | shares |  |  |  | 6,000,000 |  |  |  |
Minimum | Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, rate |  |  |  |  |  | 0.15% |  |
Maximum | Mortgage Financing Arrangement Agreement - Financing Fees | Gladstone Securities, LLC |  |  |  |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |  |  |  |
Related party transaction, rate |  |  |  |  |  | 1.00% |  |
[1] | Refer to Note 2 “Related-Party Transactions”

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