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Distributions - Costs of Investments for Tax Purposes (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
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Income Tax Disclosure [Abstract] |  |  |
Tax cost | $ 2,927,312 | $ 3,209,491 | $ 3,114,145
Gross unrealized appreciation on investments | 466,794 | 438,214 | 343,520
Gross unrealized depreciation on investments | (366,284) | (409,919) | (298,616)
Total investments at fair value | $ 3,027,822 | $ 3,237,786 | $ 3,159,049

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- Definition Amount of cost of investment for federal income tax purpose. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.6-03(h)(2)(iv)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479886/946-10-S99-3 + Details
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