DEBT - SBIC Debentures Narrative (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Payable	$ 2,007,000,000	$ 1,805,000,000
Recorded Value	$ 1,999,102,000	1,796,056,000
Unsecured Notes
Debt Instrument [Line Items]
Debt instrument, weighted-average annual interest rate	2.90%
Unsecured Notes \| SBIC debentures
Debt Instrument [Line Items]
Face amount	$ 350,000,000	350,000,000
Payable	$ 350,000,000	$ 350,000,000
Debt instrument, term	10 years
Debt instrument, weighted-average annual interest rate		2.90%
Debt instrument, remaining term	5 years 1 month 6 days
Recorded Value	$ 343,914,000	$ 342,731,000
Unsecured Notes \| SBIC debentures \| MSMF
Debt Instrument [Line Items]
Face amount	175,000,000
Recorded Value	172,000,000
Unamortized debt issuance costs	3,000,000
Unsecured Notes \| SBIC debentures \| MSC III
Debt Instrument [Line Items]
Face amount	175,000,000
Recorded Value	171,900,000
Unamortized debt issuance costs	$ 3,100,000

Debt Instrument, Remaining Term

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

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- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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