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Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) |  |  |  |  |  |  |  |  | 12 Months Ended
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Feb. 22, 2024 USD ($) | Feb. 23, 2023 USD ($) | May 06, 2022 $ / shares shares | Feb. 25, 2022 USD ($) | Dec. 23, 2020 USD ($) | Aug. 02, 2018 USD ($) $ / shares shares | Apr. 03, 2018 USD ($) | Apr. 01, 2018 USD ($) | Dec. 31, 2024 USD ($) investment segment company $ / shares shares | Dec. 31, 2023 USD ($) investment company $ / shares shares | Dec. 31, 2022 USD ($) $ / shares shares
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Repayments received/sales of portfolio investments/ Sales of short-term investments |  |  |  |  |  |  |  | $ 981,200,000 | $ 641,752,000 | $ 593,505,000 | $ 1,041,370,000
Payment for purchases of shares in repurchase plan |  |  |  |  |  |  |  |  | 6,442,000 | 14,772,000 | $ 32,105,000
Total investments at fair value |  |  |  |  |  |  |  |  | $ 2,449,272,000 | $ 2,488,715,000 |
Number of portfolio companies | company |  |  |  |  |  |  |  |  | 8 | 4 |
Number of paid-in-kind, partial non-accrual portfolio companies, originated by the company | investment |  |  |  |  |  |  |  |  | 1 |  |
Number of operating segments | segment |  |  |  |  |  |  |  |  | 1 |  |
Number of reportable segments | segment |  |  |  |  |  |  |  |  | 1 |  |
Single Portfolio Company | Percentage of Total Portfolio, at Fair Value | Portfolio Company Investment Risk |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Percent of Total Portfolio |  |  |  |  |  |  |  |  | 6.20% | 6.30% |
Sierra Merger |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of portfolio companies | company |  |  |  |  |  |  |  |  | 2 | 1 |
MVC Acquisition |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of portfolio companies | company |  |  |  |  |  |  |  |  | 1 | 1 |
Barings LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of portfolio companies | company |  |  |  |  |  |  |  |  | 5 | 2 |
Equity shares |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 409,129,000 | $ 374,704,000 |
Senior debt and 1st lien notes |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total investments at fair value |  |  |  |  |  |  |  |  | 1,686,411,000 | 1,670,300,000 |
Subordinated debt and 2nd lien notes |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total investments at fair value |  |  |  |  |  |  |  |  | 165,455,000 | 238,215,000 |
Structured Product |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 79,548,000 | $ 93,038,000 |
Investment Denominated In Canadian Dollars |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 | 2 |
Investment Denominated In Danish Kroner |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 | 1 |
Investment Denominated In Australian Dollars |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 11 | 11 |
Investment Denominated In New Zealand Dollars |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 2 | 2 |
Investment Denominated In Norwegian Krone |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 | 1 |
Investment Denominated In Swiss Francs |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 2 | 2 |
Investment Denominated In Swedish Krone |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 2 | 2 |
Investment Denominated In Euros |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 72 | 67 |
Investment Denominated In British Pounds Sterling |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 27 | 28 |
Yield Analysis | Equity shares | Market Approach |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 2 | 1 |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 20,200,000 | $ 5,300,000 |
Yield Analysis | Equity shares | Expected Recovery |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 |  |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 56,900 |  |
Yield Analysis | Senior debt and 1st lien notes | Market Approach |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 7 | 6 |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 31,500,000 | $ 20,000,000 |
Discounted Cash Flow Analysis | Senior debt and 1st lien notes | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes | Discount Rate |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  |  | 1 |
Total investments at fair value |  |  |  |  |  |  |  |  |  | $ 9,900,000 |
Discounted Cash Flow Analysis | Structured Product | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  |  | 1 |
Total investments at fair value |  |  |  |  |  |  |  |  |  | $ 3,300,000 |
Expected Recovery | Equity shares | Market Approach |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  |  | 1 |
Total investments at fair value |  |  |  |  |  |  |  |  |  | $ 0 |
Expected Recovery | Subordinated debt and 2nd lien notes | Market Approach |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 |  |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 3,800,000 |  |
Market Approach | Senior debt and 1st lien notes | Yield Analysis |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of investments | investment |  |  |  |  |  |  |  |  | 1 |  |
Total investments at fair value |  |  |  |  |  |  |  |  | $ 600,000 |  |
December 23, 2020 Program |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock aggregate amount |  |  |  |  | $ 15,000,000 |  |  |  |  |  |
Common stock market price percent of NAV, threshold |  |  |  |  | 90.00% |  |  |  |  |  |
Share repurchase program, term |  |  |  |  | 12 months |  |  |  |  |  |
Shares of common stock repurchased (in shares) | shares |  |  | 207,677 |  |  |  |  |  |  |  |
Shares of common stock repurchased, average price (in dollars per share) | $ / shares |  |  | $ 10.14 |  |  |  |  |  |  |  |
February 25, 2022 Program |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock aggregate amount |  |  |  | $ 30,000,000 |  |  |  |  |  |  |
Common stock market price percent of NAV, threshold |  |  |  | 90.00% |  |  |  |  |  |  |
Share repurchase program, term |  |  |  | 12 months |  |  |  |  |  |  |
Shares of common stock repurchased (in shares) | shares |  |  |  |  |  |  |  |  |  |  | 3,179,168
Shares of common stock repurchased, average price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  | $ 9.44
Payment for purchases of shares in repurchase plan |  |  |  |  |  |  |  |  |  |  | $ 30,000,000
February 23, 2023 Program |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock aggregate amount |  | $ 30,000,000 |  |  |  |  |  |  |  |  |
Share repurchase program, term |  | 12 months |  |  |  |  |  |  |  |  |
Shares of common stock repurchased (in shares) | shares |  |  |  |  |  |  |  |  |  | 1,894,096 |
Shares of common stock repurchased, average price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  | $ 7.99 |
February 22, 2024 Program |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock aggregate amount | $ 30,000,000 |  |  |  |  |  |  |  |  |  |
Share repurchase program, term | 12 months |  |  |  |  |  |  |  |  |  |
Shares of common stock repurchased (in shares) | shares |  |  |  |  |  |  |  |  | 658,132 |  |
Shares of common stock repurchased, average price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  | $ 9.79 |  |
Private Placement |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares issued in transaction (in shares) | shares |  |  |  |  |  | 8,529,917 |  |  |  |  |
Price per share (in dollars per share) | $ / shares |  |  |  |  |  | $ 11.723443 |  |  |  |  |
Consideration received |  |  |  |  |  | $ 100,000,000 |  |  |  |  |
Barings LLC | Payment To Shareholders | Affiliated Entity |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Related party transaction amount (up to) |  |  |  |  |  |  | $ 85,000,000 |  |  |  |
Barings LLC | Payment For Company Common Stock At Net Asset Value | Affiliated Entity |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Related party transaction amount (up to) |  |  |  |  |  |  | 100,000,000 |  |  |  |
Barings LLC | Purchase Of Common Stock At Market Value | Affiliated Entity |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Related party transaction amount (up to) |  |  |  |  |  |  | $ 50,000,000 |  |  |  |
Period of commitment |  |  |  |  |  |  | 2 years |  |  |  |

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