v3.23.3

Fee Income (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021
Revenue from Contract with Customer [Abstract] |  |  |
Fee income | $ 6,546 | $ 6,631 | $ 14,098
Recurring fee income | $ 900 | $ 900 | $ 600

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- Definition Fee Income, Recurring + References No definition available. + Details
Name: | ocsl_FeeIncomeRecurring
Namespace Prefix: | ocsl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Amount of fee income including, but not limited to, managerial assistance, servicing of investment, and origination and commitment fees. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07(1)(c)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1 + Details
Name: | us-gaap_FeeIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration