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Fair Value Measurements - Reconciliation of Beginning and Ending Balances for Investments at Fair Value that Use Level 3 Inputs (Details) $ in Thousands | 3 Months Ended
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Mar. 31, 2024 USD ($) investment | Mar. 31, 2023 USD ($)
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Balance at the beginning | $ 455,007 | $ 505,237
Purchases of investments and other adjustments to cost | 26,708 | 24,946
Proceeds from principal payments and sales of investments | (12,087) | (30,404)
Reclassifications | 0 |
Transfers in (out) of Level 3 | (335) |
Balance at the end | 466,879 | 496,038
Total net change in unrealized gain (loss) on investments attributable to Level 3 investments still held | $ (2,451) | (3,645)
Number of investments transferred from level 3 | investment | 1,000 |
Net realized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | $ 4 | 706
Net change in unrealized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | (2,418) | (4,447)
Senior secured loans |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Balance at the beginning | 388,882 | 434,023
Purchases of investments and other adjustments to cost | 23,576 | 23,577
Proceeds from principal payments and sales of investments | (4,038) | (21,451)
Reclassifications | (2,712) |
Transfers in (out) of Level 3 | 0 |
Balance at the end | 404,051 | 431,880
Senior secured loans | Net realized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | 0 | 0
Senior secured loans | Net change in unrealized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | (1,657) | (4,269)
Unitranche secured loans |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Balance at the beginning | 13,877 | 20,633
Purchases of investments and other adjustments to cost | 100 | 45
Proceeds from principal payments and sales of investments | (7,785) | (7,320)
Reclassifications | 0 |
Transfers in (out) of Level 3 | 0 |
Balance at the end | 6,091 | 13,361
Unitranche secured loans | Net realized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | 0 | 0
Unitranche secured loans | Net change in unrealized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | (101) | 3
Junior secured loans |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Balance at the beginning | 26,594 | 22,193
Purchases of investments and other adjustments to cost | 1,087 | 569
Proceeds from principal payments and sales of investments | (260) | (927)
Reclassifications | (1,407) |
Transfers in (out) of Level 3 | 0 |
Balance at the end | 27,427 | 21,978
Junior secured loans | Net realized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | 0 | 0
Junior secured loans | Net change in unrealized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | 1,413 | 143
Equity securities |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Balance at the beginning | 25,654 | 28,388
Purchases of investments and other adjustments to cost | 1,945 | 755
Proceeds from principal payments and sales of investments | (4) | (706)
Reclassifications | 4,119 |
Transfers in (out) of Level 3 | (335) |
Balance at the end | 29,310 | 28,819
Equity securities | Net realized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | 4 | 706
Equity securities | Net change in unrealized gain (loss) on investments |  |
Reconciliation of beginning and ending balances for investments at fair value that use Level 3 inputs |  |
Net realized gain (loss) on investments | $ (2,073) | $ (324)

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- Definition Amount of increase (decrease) in fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing, arising from reclassifications. + References No definition available. + Details
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