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Fair Value Measurements - Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands | Mar. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | $ 9,626,202 | $ 9,617,248
First lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 9,425,003 | 9,419,963
Second lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 46,678 | 46,336
Investments in equity |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 154,521 | 150,949
Level 1 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 1 | First lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 1 | Second lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 1 | Investments in equity |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 2 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 199,713 | 144,452
Level 2 | First lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 199,713 | 144,452
Level 2 | Second lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 2 | Investments in equity |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 0 | 0
Level 3 |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 9,426,489 | 9,472,796
Level 3 | First lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 9,225,290 | 9,275,511
Level 3 | Second lien debt |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | 46,678 | 46,336
Level 3 | Investments in equity |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Total | $ 154,521 | $ 150,949

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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258 + Details
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