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INVESTMENTS - Schedule of Changes in Level 3 Fair Value Measurements of Investments (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Jun. 30, 2024 | Mar. 31, 2024 | Jun. 30, 2023 | Mar. 31, 2023
Old World Christmas, Inc. |  |  |  |  |  |  |  |
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Realized gain (loss) on preferred equity |  |  |  | $ 300 |  |  |  |
Total |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | $ 853,307 | $ 915,614 | $ 853,307 | 915,614 | $ 899,138 | $ 920,486 | $ 800,047 | $ 753,516
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Issuances / originations | 19,500 | 66,813 | 20,098 | 114,788 |  |  |  |
Settlements / repayments | (25,000) | 0 | (28,000) | 0 |  |  |  |
Sales | (48,503) | 0 | (48,503) | (1,775) |  |  |  |
Transfers | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 853,307 | 915,614 | 853,307 | 915,614 |  |  |  |
Total | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 42,284 | 0 | 42,284 | 1,155 |  |  |  |
Total | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 3,916 | 48,754 | (15,030) | 48,023 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | (38,028) | 0 | (38,028) | (93) |  |  |  |
Secured First Lien Debt |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 469,480 | 508,504 | 469,480 | 508,504 | 463,219 | 474,856 | 452,215 | 437,517
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Issuances / originations | 19,500 | 55,400 | 20,098 | 70,100 |  |  |  |
Settlements / repayments | 0 | 0 | (3,000) | 0 |  |  |  |
Sales | 0 | 0 | 0 | 0 |  |  |  |
Transfers | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 469,480 | 508,504 | 469,480 | 508,504 |  |  |  |
Secured First Lien Debt | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 0 | 0 | 0 | 0 |  |  |  |
Secured First Lien Debt | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | (13,239) | 889 | (22,474) | 887 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | 0 | 0 | 0 | 0 |  |  |  |
Secured Second Lien Debt |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 111,344 | 102,747 | 111,344 | 102,747 | 137,827 | 138,703 | 104,794 | 75,734
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Issuances / originations | 0 | 0 | 0 | 25,000 |  |  |  |
Settlements / repayments | (25,000) | 0 | (25,000) | 0 |  |  |  |
Sales | 0 | 0 | 0 | 0 |  |  |  |
Transfers | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 111,344 | 102,747 | 111,344 | 102,747 |  |  |  |
Secured Second Lien Debt | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 0 | 0 | 0 | 0 |  |  |  |
Secured Second Lien Debt | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | (1,483) | (2,047) | (2,359) | 2,013 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | 0 | 0 | 0 | 0 |  |  |  |
Preferred Equity |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 228,528 | 267,596 | 228,528 | 267,596 | 212,591 | 213,480 | 214,258 | 222,585
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Issuances / originations | 0 | 11,413 | 0 | 14,688 |  |  |  |
Settlements / repayments | 0 | 0 | 0 | 0 |  |  |  |
Sales | 0 | 0 | 0 | (273) |  |  |  |
Transfers | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 228,528 | 267,596 | 228,528 | 267,596 |  |  |  |
Preferred Equity | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 0 | 0 | 0 | 273 |  |  |  |
Preferred Equity | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 15,937 | 41,925 | 15,048 | 30,323 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | 0 | 0 | 0 | 0 |  |  |  |
Common Equity/ Equivalents |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Beginning balance | 43,955 | 36,767 | 43,955 | 36,767 | $ 85,501 | $ 93,447 | $ 28,780 | $ 17,680
New investments, repayments and settlements: |  |  |  |  |  |  |  |
Issuances / originations | 0 | 0 | 0 | 5,000 |  |  |  |
Settlements / repayments | 0 | 0 | 0 | 0 |  |  |  |
Sales | (48,503) | 0 | (48,503) | (1,502) |  |  |  |
Transfers | 0 | 0 | 0 | 0 |  |  |  |
Ending balance | 43,955 | 36,767 | 43,955 | 36,767 |  |  |  |
Common Equity/ Equivalents | Debt and Equity Securities, Realized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 42,284 | 0 | 42,284 | 882 |  |  |  |
Common Equity/ Equivalents | Debt and Equity Securities, Unrealized Gain (Loss) |  |  |  |  |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |  |  |  |  |
Total gain (loss) | 2,701 | 7,987 | (5,245) | 14,800 |  |  |  |
Reversal of previously recorded (appreciation) depreciation upon realization | $ (38,028) | $ 0 | $ (38,028) | $ (93) |  |  |  |

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