XML 55 R44.htm IDEA: XBRL DOCUMENT
v3.25.3

BORROWINGS - Narrative (Details) |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 6 Months Ended |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 09, 2024 USD ($) | Nov. 04, 2024 USD ($) trading_day $ / shares | Mar. 20, 2024 USD ($) | Mar. 01, 2024 | Aug. 02, 2023 USD ($) | Apr. 20, 2021 USD ($) | Aug. 31, 2021 USD ($) | Sep. 30, 2025 USD ($) lender facility $ / shares | Dec. 31, 2024 USD ($) | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) facility lender consecutive_trading_day $ / shares | Sep. 30, 2024 USD ($) | Jun. 20, 2024 USD ($) | Jun. 19, 2024 USD ($) | Aug. 01, 2023 USD ($) | Jun. 30, 2023 USD ($) | Nov. 30, 2021 USD ($) | Feb. 28, 2021 USD ($) | Dec. 31, 2020 USD ($) | Apr. 25, 2019
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asset coverage ratio |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 166.00%
Current asset coverage ratio |  |  |  |  |  |  |  | 208.00% |  |  | 208.00% |  |  |  |  |  |  |  |  |
January 2026 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 0.00% |  | 4.46% | 0.00% | 4.46% |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 65,000,000 | $ 75,000,000 |
Fixed interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.50% |
Issuance price percent received |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 102.11% |  |
Yield-to-maturity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.00% |  |
Repurchased face amount | $ 140,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Redemption price, percentage | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Realized loss on disposal of fixed assets |  |  |  |  |  |  |  |  | $ 400,000 |  |  |  |  |  |  |  |  |  |  |
October 2026 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 3.50% |  | 3.50% | 3.50% | 3.50% |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  | $ 100,000,000 |  |  |  |  |  |  |  |  |  | $ 50,000,000 |  |  |
Fixed interest rate |  |  |  |  |  |  | 3.375% |  |  |  |  |  |  |  |  |  | 3.375% |  |  |
Issuance price percent received |  |  |  |  |  |  | 99.418% |  |  |  |  |  |  |  |  |  | 99.993% |  |  |
Yield-to-maturity |  |  |  |  |  |  | 3.50% |  |  |  |  |  |  |  |  |  | 3.375% |  |  |
Redemption price, percentage |  |  |  |  |  |  | 100.00% |  |  |  | 100.00% |  |  |  |  |  |  |  |  |
October 2026 Notes | Convertible Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fixed interest rate |  | 5.125% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
August 2028 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 7.75% |  | 7.75% | 7.75% | 7.75% |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 71,900,000 |  |  |  |
Fixed interest rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7.75% |  |  |  |
August 2028 Notes Overallotment | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 9,400,000 |  |  |  |
2029 Convertible Notes | Convertible Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 5.13% |  | 0.00% | 5.13% | 0.00% |  |  |  |  |  |  |  |
Aggregate principal amount |  | $ 230,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fixed interest rate |  | 5.125% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Redemption price, percentage |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |
Conversion rate |  | 0.04 |  |  |  |  |  |  |  |  | 40.43 |  |  |  |  |  |  |  |  |
Conversion price (in usd per share) | $ / shares |  | $ 25.00 |  |  |  |  |  | $ 24.73 |  |  | $ 24.73 |  |  |  |  |  |  |  |  |
Dividend increase (in usd per share) | $ / shares |  |  |  |  |  |  |  | $ 0.58 |  |  | $ 0.58 |  |  |  |  |  |  |  |  |
Percentage of stock price |  | 130.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Trading days | trading_day |  | 20 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Consecutive trading days | consecutive_trading_day |  |  |  |  |  |  |  |  |  |  | 30 |  |  |  |  |  |  |  |  |
2029 Convertible Notes | Convertible Debt | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Conversion rate |  |  |  |  |  |  |  |  |  |  | 0.0447828 |  |  |  |  |  |  |  |  |
2029 Convertible Notes Overallotement | Convertible Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount |  | $ 30,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
September 2030 Notes | Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 5.95% |  | 0.00% | 5.95% | 0.00% |  |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  |  | $ 350,000,000 |  |  | $ 350,000,000 |  |  |  |  |  |  |  |  |
Fixed interest rate |  |  |  |  |  |  |  | 5.95% |  |  | 5.95% |  |  |  |  |  |  |  |  |
Issuance price percent received |  |  |  |  |  |  |  | 99.345% |  |  | 99.345% |  |  |  |  |  |  |  |  |
Yield-to-maturity |  |  |  |  |  |  |  | 6.104% |  |  | 6.104% |  |  |  |  |  |  |  |  |
Redemption price, percentage |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |
SBA Debentures | Unsecured Debt |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 4.45% |  | 4.43% | 4.43% | 4.41% |  |  |  |  |  |  |  |
SBA Debentures | Unsecured Debt | SBIC I |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maturity |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory maximum borrowing capacity |  |  |  |  |  | $ 175,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory capital |  |  |  |  |  | $ 87,500,000 |  | $ 87,500,000 |  |  | $ 87,500,000 |  |  |  |  |  |  |  |  |
Available leverage commitment |  |  |  |  |  |  |  | 87,500,000 |  |  | 87,500,000 |  |  |  |  |  |  |  |  |
Leverage commitment amount |  |  |  |  |  |  |  | 175,000,000 |  |  | 175,000,000 |  |  |  |  |  |  |  |  |
SBA Debentures | Unsecured Debt | SBIC II |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory capital |  |  |  |  |  |  |  | 87,500,000 |  |  | 87,500,000 |  |  |  |  |  |  |  |  |
Available leverage commitment |  |  |  |  |  |  |  | 26,000,000 |  |  | 26,000,000 |  |  |  |  |  |  |  |  |
Leverage commitment amount |  |  |  |  |  |  |  | $ 40,000,000 |  |  | $ 40,000,000 |  |  |  |  |  |  |  |  |
Corporate Credit Facility | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 6.79% |  |  | 6.76% |  |  |  |  |  |  |  |  |
Average borrowings |  |  |  |  |  |  |  | $ 315,400,000 |  |  | $ 317,500,000 |  |  |  |  |  |  |  |  |
Corporate Credit Facility | Corporate Credit Facility | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of revolving credit facility | facility |  |  |  |  |  |  |  | 1 |  |  | 1 |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 6.72% |  | 7.74% | 6.68% | 7.75% |  |  |  |  |  |  |  |
Average borrowings |  |  |  |  |  |  |  | $ 202,391,000 |  | $ 166,685,000 | $ 205,328,000 | $ 178,579,000 |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  |  |  | 2.15% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  | $ 435,000,000 |  |  | $ 510,000,000 |  |  | $ 510,000,000 |  |  |  | $ 400,000,000 |  |  |  |  |
Accordion feature increase limit |  |  |  |  | $ 750,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of lenders | lender |  |  |  |  |  |  |  | 11 |  |  | 11 |  |  |  |  |  |  |  |  |
Minimum senior coverage ratio |  |  |  | 2.00 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum asset coverage ratio |  |  |  | 1.50 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest coverage ratio |  |  |  | 2.00 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate Credit Facility | Corporate Credit Facility | Line of Credit | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  |  | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate Credit Facility | Corporate Credit Facility | Line of Credit | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SPV Credit Facility | SPV Credit Facility | Line of Credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of revolving credit facility | facility |  |  |  |  |  |  |  | 1 |  |  | 1 |  |  |  |  |  |  |  |  |
Weighted average interest rate |  |  |  |  |  |  |  | 6.92% |  | 7.85% | 6.90% | 7.87% |  |  |  |  |  |  |  |
Average borrowings |  |  |  |  |  |  |  | $ 112,967,000 |  | $ 70,826,000 | $ 112,202,000 | $ 58,617,000 |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  | $ 150,000,000 |  |  |  |  |  |  |  |  |  |  | $ 150,000,000 |  |  |  |  |  |
Accordion feature increase limit |  |  |  |  |  |  |  |  |  |  |  |  | $ 200,000,000 |  |  |  |  |  |  |
Accordion feature that allows increases (up to) |  |  | $ 400,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SPV Credit Facility | SPV Credit Facility | Line of Credit | Before March 20 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  | 2.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SPV Credit Facility | SPV Credit Facility | Line of Credit | After March 20 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  | 2.85% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SPV Credit Facility | SPV Credit Facility | Line of Credit | Before April 20 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  | 0.10% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
SPV Credit Facility | SPV Credit Facility | Line of Credit | After April 20 2024 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  | 0.35% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Debt Instrument, Convertible, Per Share Dividend Threshold + References No definition available. + Details
Name: | cswc_DebtInstrumentConvertiblePerShareDividendThreshold
Namespace Prefix: | cswc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Covenant, Interest Coverage Ratio, Minimum + References No definition available. + Details
Name: | cswc_DebtInstrumentCovenantInterestCoverageRatioMinimum
Namespace Prefix: | cswc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Covenant, Regulatory Asset Coverage Ratio, Minimum + References No definition available. + Details
Name: | cswc_DebtInstrumentCovenantRegulatoryAssetCoverageRatioMinimum
Namespace Prefix: | cswc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Covenant, Senior Coverage Ratio, Minimum + References No definition available. + Details
Name: | cswc_DebtInstrumentCovenantSeniorCoverageRatioMinimum
Namespace Prefix: | cswc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Issuance Price, Percent Of Principal Amount + References No definition available. + Details
Name: | cswc_DebtInstrumentIssuancePricePercentOfPrincipalAmount
Namespace Prefix: | cswc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Leverage Commitment Amount + References No definition available. + Details
Name: | cswc_DebtInstrumentLeverageCommitmentAmount
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Debt Instrument, Regulatory Maximum Borrowing Capacity + References No definition available. + Details
Name: | cswc_DebtInstrumentRegulatoryMaximumBorrowingCapacity
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Debt Instrument, Yield-To-Maturity At Issuance + References No definition available. + Details
Name: | cswc_DebtInstrumentYieldToMaturityAtIssuance
Namespace Prefix: | cswc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Investment Company, Senior Security, Indebtedness, Asset Coverage Ratio, Minimum Threshold + References No definition available. + Details
Name: | cswc_InvestmentCompanySeniorSecurityIndebtednessAssetCoverageRatioMinimumThreshold
Namespace Prefix: | cswc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Leverageable Capital + References No definition available. + Details
Name: | cswc_LeverageableCapital
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option + References No definition available. + Details
Name: | cswc_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of Credit Facility, Accordion Feature, Increase Limit + References No definition available. + Details
Name: | cswc_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number Of Lenders + References No definition available. + Details
Name: | cswc_NumberOfLenders
Namespace Prefix: | cswc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Revolving Credit Facility + References No definition available. + Details
Name: | cswc_NumberOfRevolvingCreditFacility
Namespace Prefix: | cswc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Regulatory Capital + References No definition available. + Details
Name: | cswc_RegulatoryCapital
Namespace Prefix: | cswc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-5 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(5)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-7 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-6 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentConvertibleThresholdTradingDays
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482949/835-30-55-8 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- 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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482949/835-30-55-8 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69E -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E Reference 12: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69F -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69F Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 15: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1D -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1E -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 27: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 28: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1I -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I Reference 30: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 Reference 31: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 + Details
Name: | us-gaap_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage price of original principal amount of debt at which debt can be redeemed by the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 470 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477734/942-470-50-3 + Details
Name: | us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of the original debt instrument that was repurchased. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentRepurchasedFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of total assets less all liabilities and indebtedness not represented by senior security, to senior security representing indebtedness. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name Investment Company Act of 1940 -Section 61 -Paragraph a -Subparagraph (1) -Publisher SEC + Details
Name: | us-gaap_InvestmentCompanySeniorSecurityIndebtednessAssetCoverageRatio
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Average amount borrowed under the credit facility during the period. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityAverageOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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 Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Weighted average interest rate of long-term debt outstanding calculated over time. + References No definition available. + Details
Name: | us-gaap_LongTermDebtWeightedAverageInterestRateOverTime
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(8)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_January2026NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_MediumTermNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_October2026NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_August2028NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_August2028NotesOverallotmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_A2029ConvertibleNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_A2029ConvertibleNotesOverallotementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_September2030NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_SmallBusinessAdministrationDebenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=cswc_SBICIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=cswc_SBICIIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_CorporateCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=cswc_SpecialPurposeVehicleFinancingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cswc_DebtInstrumentRatePeriodAxis=cswc_BeforeMarch202027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cswc_DebtInstrumentRatePeriodAxis=cswc_AfterMarch202027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cswc_DebtInstrumentRatePeriodAxis=cswc_BeforeApril202024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | cswc_DebtInstrumentRatePeriodAxis=cswc_AfterApril202024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |