Investments - Selected Balance Sheet Information for SLP III and SLP IV (Details) - USD ($) $ in Thousands |
Sep. 30, 2022 |
Dec. 31, 2021 |
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|---|---|---|---|---|---|---|---|---|
| Investment Company, Nonconsolidated Subsidiary [Line Items] | ||||||||
| Investments, cost | $ 3,258,903 | [1] | $ 3,126,492 | [2] | ||||
| Investments at fair value | 3,234,433 | [1] | 3,174,364 | [2] | ||||
| Total assets | 3,347,993 | 3,295,812 | ||||||
| Deferred financing costs, accumulated amortization | 45,794 | 40,713 | ||||||
| Deferred financing costs (net of accumulated amortization) | (15,316) | (19,684) | ||||||
| Payable for unsettled securities purchased | 0 | 7,910 | ||||||
| Other liabilities | 6,731 | 2,478 | ||||||
| Total liabilities | 2,002,895 | 1,953,200 | ||||||
| Total liabilities and net assets | 3,347,993 | 3,295,812 | ||||||
| SLP III | ||||||||
| Investment Company, Nonconsolidated Subsidiary [Line Items] | ||||||||
| Investments, cost | 672,350 | 701,743 | ||||||
| Investments at fair value | 635,750 | 702,148 | ||||||
| Cash and other assets | 25,474 | 16,505 | ||||||
| Receivable from unsettled securities sold | 0 | 7,351 | ||||||
| Total assets | 661,224 | 726,004 | ||||||
| Deferred financing costs, accumulated amortization | 3,708 | 3,338 | ||||||
| Deferred financing costs (net of accumulated amortization) | (2,074) | (3,198) | ||||||
| Payable for unsettled securities purchased | 13,079 | 34,552 | ||||||
| Distribution payable | 4,922 | 5,031 | ||||||
| Other liabilities | 5,059 | 2,378 | ||||||
| Total liabilities | 522,486 | 549,663 | ||||||
| Members' capital | 138,738 | 176,341 | ||||||
| Total liabilities and net assets | 661,224 | 726,004 | ||||||
| SLP III | Revolving Credit Facility | ||||||||
| Investment Company, Nonconsolidated Subsidiary [Line Items] | ||||||||
| Credit facility | 501,500 | 510,900 | ||||||
| SLP IV | ||||||||
| Investment Company, Nonconsolidated Subsidiary [Line Items] | ||||||||
| Investments, cost | 501,129 | 505,043 | ||||||
| Investments at fair value | 475,893 | 504,948 | ||||||
| Cash and other assets | 15,697 | 12,912 | ||||||
| Receivable from unsettled securities sold | 0 | 2,595 | ||||||
| Total assets | 491,590 | 520,455 | ||||||
| Deferred financing costs, accumulated amortization | 845 | 396 | ||||||
| Deferred financing costs (net of accumulated amortization) | (2,160) | (2,609) | ||||||
| Payable for unsettled securities purchased | 7,493 | 13,893 | ||||||
| Distribution payable | 4,022 | 3,396 | ||||||
| Other liabilities | 4,178 | 1,910 | ||||||
| Total liabilities | 373,070 | 376,727 | ||||||
| Members' capital | 118,520 | 143,728 | ||||||
| Total liabilities and net assets | 491,590 | 520,455 | ||||||
| SLP IV | Revolving Credit Facility | ||||||||
| Investment Company, Nonconsolidated Subsidiary [Line Items] | ||||||||
| Credit facility | $ 359,537 | $ 360,137 | ||||||
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