SUBSEQUENT EVENTS (Details) - Subsequent Event $ / shares in Units, $ in Millions	Aug. 07, 2026 USD ($) $ / shares
MSC Income Fund Rule 10b5-1 Stock Repurchase Plan and Main Street Rule 10b5-1 Purchase Plan
Subsequent Event [Line Items]
Share repurchase program, authorized, amount \| $	$ 40.0
MSC Income Fund Rule 10b5-1 Stock Repurchase Plan
Subsequent Event [Line Items]
Share repurchase program, authorized, amount \| $	20.0
Purchase Commitments
Subsequent Event [Line Items]
Share repurchase program, authorized, amount \| $	$ 20.0
O 2026 M10 Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	$ 0.11
O 2026 M11 Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	0.11
O 2026 M12 Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	0.11
O 2026 Q4 Regular Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	0.33
O 2026 Q4 Supplemental Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	0.03
O 2026 Q4 Dividends
Subsequent Event [Line Items]
Cash dividend (in dollars per share)	$ 0.36

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

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Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480070/505-10-S50-1

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Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

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