Investment Company, Financial Commitment to Investee, Unrealized Appreciation (Depreciation)

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of financial support to be provided in future by investment company to investee.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=66023616&loc=SL35737436-115832

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

+ Details

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- Details

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- Details

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- Details

Name:	us-gaap_InvestmentTypeAxis=fsk_DebtSecuritiesDelayedDrawTermLoanMember
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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Commitment and Contingencies - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Jun. 29, 2022	May 17, 2022	May 16, 2022	Dec. 31, 2021
Debt Securities
Other Commitments [Line Items]
Unfunded commitments	$ 1,042,400					$ 1,724,100
Unrealized appreciation (depreciation) on unfunded commitments	(18,200)
Debt Securities, Revolving Credit Facility
Other Commitments [Line Items]
Unfunded commitments	402,000
Debt Securities, Delayed Draw Term Loan
Other Commitments [Line Items]
Unfunded commitments	640,400
Partnership Interest \| Credit Opportunities Partners JV, LLC
Other Commitments [Line Items]
Unfunded commitments	560,200					350,200
Revolving Credit Facility \| Senior Secured Revolving Credit Facility
Other Commitments [Line Items]
Long-term line of credit						$ 9,000
Revolving Credit Facility \| Senior Secured Revolving Credit Facility \| Line of Credit
Other Commitments [Line Items]
Amount outstanding		$ 4,655,000	$ 4,640,000	$ 4,640,000	$ 4,025,000
Letter of Credit \| Senior Secured Revolving Credit Facility \| Line of Credit
Other Commitments [Line Items]
Amount outstanding	175,000
Standby Letters of Credit \| Senior Secured Revolving Credit Facility \| Line of Credit
Other Commitments [Line Items]
Long-term line of credit	$ 12,000