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N-2 - $ / shares | 3 Months Ended |  |  |
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Jun. 30, 2023 | Mar. 31, 2023 | Jun. 30, 2022 | Mar. 31, 2022
Cover [Abstract] |  |  |  |
Entity Central Index Key | 0000017313 |  |  |
Amendment Flag | false |  |  |
Securities Act File Number | 814-00061 |  |  |
Document Type | 10-Q |  |  |
Entity Registrant Name | CAPITAL SOUTHWEST CORPORATION |  |  |
Entity Address, Address Line One | 8333 Douglas Avenue |  |  |
Entity Address, Address Line Two | Suite 1100 |  |  |
Entity Address, City or Town | Dallas |  |  |
Entity Address, State or Province | TX |  |  |
Entity Address, Postal Zip Code | 75225 |  |  |
City Area Code | 214 |  |  |
Local Phone Number | 238-5700 |  |  |
Entity Emerging Growth Company | false |  |  |
General Description of Registrant [Abstract] |  |  |  |
Risk Factors [Table Text Block] | Risk Factors Investing in our common stock involves a number of significant risks. There have been no material changes to the risk factors as previously disclosed in our Annual Report on Form 10-K for the fiscal year ended March 31, 2023 that we filed with the SEC on May 23, 2023, other than the risk factor listed below: The alternative reference rates that have replaced LIBOR in our credit arrangements and other financial instruments may not yield the same or similar economic results as LIBOR over the life of such transactions. The London Interbank Offered Rate (“LIBOR”) is an index rate that historically was widely used in lending transactions and was a common reference rate for setting the floating interest rate on private loans. LIBOR was typically the reference rate used in floating-rate loans extended to our portfolio companies. The ICE Benchmark Administration (“IBA”) (the entity that is responsible for calculating LIBOR) ceased providing overnight, one, three, six and twelve months USD LIBOR tenors on June 30, 2023. In addition, the United Kingdom’s Financial Conduct Authority (“FCA”), which oversees the IBA, now prohibits entities supervised by the FCA from using LIBORs, including USD LIBOR, except in very limited circumstances. In the United States, the Secured Overnight Financing Rate (“SOFR”) is the preferred alternative rate for LIBOR. SOFR is a measure of the cost of borrowing cash overnight, collateralized by U.S. Treasury securities, and is based on directly observable U.S. Treasury-backed repurchase transactions. SOFR is published by the Federal Reserve Bank of New York each U.S. Government Securities Business Day, for transactions made on the immediately preceding U.S. Government Securities Business Day. Alternative reference rates that may replace LIBOR, including SOFR for USD transactions, may not yield the same or similar economic results as LIBOR over the lives of such transactions. Substantially all of our loans that referenced LIBOR have been amended to reference the forward-looking term rate published by CME Group Benchmark Administration Limited based on the secured overnight financing rate (“CME Term SOFR”). CME Term SOFR rates are forward-looking rates that are derived by compounding projected overnight SOFR rates over one, three, and six months taking into account the values of multiple consecutive, executed, one-month and three-month CME Group traded SOFR futures contracts and, in some cases, over-the-counter SOFR Overnight Indexed Swaps as an indicator of CME Term SOFR reference rate values. CME Term SOFR and the inputs on which it is based are derived from SOFR. Since CME Term SOFR is a relatively new market rate, there will likely be no established trading market for credit agreements or other financial instruments when they are issued, and an established market may never develop or may not be liquid. Market terms for instruments referencing CME Term SOFR rates may be lower than those of later-issued CME Term SOFR indexed instruments. Similarly, if CME Term SOFR does not prove to be widely used, the trading price of instruments referencing CME Term SOFR may be lower than those of instruments indexed to indices that are more widely used. |  |  |
NAV Per Share | $ 16.38 | $ 16.37 | $ 16.54 | $ 16.86
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt [Table Text Block] | In accordance with the 1940 Act, effective April 25, 2019, the Company is only allowed to borrow amounts such that its asset coverage (i.e., the ratio of assets less liabilities not represented by senior securities to senior securities such as borrowings), calculated pursuant to the 1940 Act, is at least 150% after such borrowing. The Board of Directors also approved a resolution that limits the Company’s issuance of senior securities such that the asset coverage ratio, taking into account any such issuance, would not be less than 166%, which became effective April 25, 2019. On August 11, 2021, we received an exemptive order from SEC to permit us to exclude the senior securities issued by SBIC I or any future SBIC subsidiary of the Company from the definition of senior securities in the asset coverage requirement applicable to the Company under the 1940 Act. As of June 30, 2023, the Company’s asset coverage was 237%. Credit Facility In August 2016, CSWC entered into a senior secured revolving credit facility (the “Credit Facility”) to provide additional liquidity to support its investment and operational activities. On August 9, 2021, CSWC entered into the Second Amended and Restated Senior Secured Revolving Credit Agreement (as amended or otherwise modified from time to time, the "Credit Agreement"). Prior to the Credit Agreement, (1) borrowings under the Credit Facility accrued interest on a per annum basis at a rate equal to the applicable LIBOR rate plus 2.50% with no LIBOR floor, and (2) the total borrowing capacity was $340 million with commitments from a diversified group of eleven lenders. The Credit Agreement (1) decreased the total borrowing capacity under the Credit Facility to $335 million with commitments from a diversified group of ten lenders, (2) reduced the interest rate on borrowings to LIBOR plus 2.15% with no LIBOR floor and removed conditions related thereto as previously set forth in the Amended and Restated Senior Secured Revolving Credit Agreement, and (3) extended the end of the Credit Facility's revolver period from December 21, 2022 to August 9, 2025 and extended the final maturity from December 21, 2023 to August 9, 2026. The Credit Agreement also modified certain covenants in the Credit Facility, including, among other things, to increase the minimum obligors’ net worth test from $180 million to $200 million. The Credit Facility contains an accordion feature that allows CSWC to increase the total commitments under the Credit Facility up to $400 million from new and existing lenders on the same terms and conditions as the existing commitments. On May 11, 2022, CSWC entered into Amendment No. 2 (the "Amendment") to the Credit Agreement. The Amendment changed the benchmark interest rate from LIBOR to Adjusted Term SOFR. In addition, on May 11, 2022, CSWC entered into an Incremental Commitment Agreement, pursuant to which the total commitments under the Credit Agreement increased from $335 million to $380 million. On November 16, 2022, CSWC entered into an Incremental Assumption Agreement that increased the total commitments of the Credit Agreement by $20 million, which increased total commitments from $380 million to $400 million. The $20 million increase was provided by one existing lender and one new lender, bringing the total bank syndicate to eleven participants. CSWC pays unused commitment fees of 0.50% to 1.00% per annum, based on utilization, on the unused lender commitments under the Credit Facility. The Credit Facility contains certain affirmative and negative covenants, including but not limited to: (1) certain reporting requirements, (2) maintaining RIC and BDC status, (3) maintaining a minimum senior coverage ratio of 2 to 1, (4) maintaining a minimum shareholders’ equity, (5) maintaining a minimum consolidated net worth, (6) maintaining a regulatory asset coverage of not less than 150%, (7) maintaining an interest coverage ratio of at least 2.25 to 1.0, and (8) at any time the outstanding advances exceed 90% of the borrowing base, maintaining a minimum liquidity of not less than 10% of the covered debt amount. The Credit Agreement also contains customary events of default, including, without limitation, nonpayment, misrepresentation of representations and warranties in a material respect, breach of covenant, bankruptcy, and change of control, with customary cure and notice provisions. If the Company defaults on its obligations under the Credit Agreement, the lenders may have the right to foreclose upon and sell, or otherwise transfer, the collateral subject to their security interests. The Credit Facility is secured by (1) substantially all of the present and future property and assets of the Company and the guarantors and (2) 100% of the equity interests in the Company’s wholly-owned subsidiary. As of June 30, 2023, substantially all of the Company’s assets were pledged as collateral for the Credit Facility, except for assets held in SBIC I. At June 30, 2023, CSWC had $195.0 million in borrowings outstanding under the Credit Facility. CSWC recognized interest expense related to the Credit Facility, including unused commitment fees and amortization of deferred loan costs, of $4.9 million and $1.9 million for the three months ended June 30, 2023 and 2022, respectively. The weighted average interest rate on the Credit Facility was 7.36% and 3.16% for the three months ended June 30, 2023 and 2022, respectively. Average borrowings for the three months ended June 30, 2023 and 2022 were $239.7 million and $182.9 million, respectively. As of June 30, 2023 and 2022, CSWC was in compliance with all financial covenants under the Credit Agreement. January 2026 Notes In December 2020, the Company issued $75.0 million in aggregate principal amount of 4.50% Notes due 2026 (the "Existing January 2026 Notes"). The Existing January 2026 Notes were issued at par. In February 2021, the Company issued an additional $65.0 million in aggregate principal amount of the January 2026 Notes (the "Additional January 2026 Notes" together with the Existing January 2026 Notes, the "January 2026 Notes"). The Additional January 2026 Notes were issued at a price of 102.11% of the aggregate principal amount of the Additional January 2026 Notes, resulting in a yield-to-maturity of approximately 4.0% at issuance. The Additional January 2026 Notes are treated as a single series with the Existing January 2026 Notes under the indenture and have the same terms as the Existing January 2026 Notes. The January 2026 Notes mature on January 31, 2026 and may be redeemed in whole or in part at any time prior to October 31, 2025, at par plus a "make-whole" premium, and thereafter at par. The January 2026 Notes bear interest at a rate of 4.50% per year, payable semi-annually on January 31 and July 31 of each year. The January 2026 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under the Credit Facility and the SBA Debentures. As of June 30, 2023, the carrying amount of the January 2026 Notes was $139.1 million on an aggregate principal amount of $140.0 million at a weighted average effective yield of 4.46%. As of June 30, 2023, the fair value of the January 2026 Notes was $118.4 million. This is a Level 3 fair value measurement under ASC 820 based on a valuation model using a discounted cash flow analysis. The Company recognized interest expense related to the January 2026 Notes, including amortization of deferred issuance costs, of $1.7 million for each of the three months ended June 30, 2023 and 2022. For each of the three months ended June 30, 2023 and 2022, average borrowings were $140.0 million. The indenture governing the January 2026 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the January 2026 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). These covenants are subject to important limitations and exceptions that are described in the indenture and the third supplemental indenture relating to the January 2026 Notes. In addition, holders of the January 2026 Notes can require the Company to repurchase some or all of the January 2026 Notes at a purchase price equal to 100% of their principal amount, plus accrued and unpaid interest to, but not including, the repurchase date upon the occurrence of a “Change of Control Repurchase Event,” as defined in the third supplemental indenture relating to the January 2026 Notes. October 2026 Notes In August 2021, the Company issued $100.0 million in aggregate principal amount of 3.375% Notes due 2026 (the "Existing October 2026 Notes"). The Existing October 2026 Notes were issued at a price of 99.418% of the aggregate principal amount of the Existing October 2026 Notes, resulting in a yield-to-maturity of 3.5%. In November 2021, the Company issued an additional $50.0 million in aggregate principal amount of the October 2026 Notes (the "Additional October 2026 Notes" together with the Existing October 2026 Notes, the "October 2026 Notes"). The Additional October 2026 Notes were issued at a price of 99.993% of the aggregate principal amount, resulting in a yield-to-maturity of approximately 3.375% at issuance. The Additional October 2026 Notes are treated as a single series with the Existing October 2026 Notes under the indenture and have the same terms as the Existing October 2026 Notes. The October 2026 Notes mature on October 1, 2026 and may be redeemed in whole or in part at any time prior to July 1, 2026, at par plus a "make-whole" premium, and thereafter at par. The October 2026 Notes bear interest at a rate of 3.375% per year, payable semi-annually in arrears on April 1 and October 1 of each year. The October 2026 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under the Credit Facility and the SBA Debentures. As of June 30, 2023, the carrying amount of the October 2026 Notes was $147.4 million on an aggregate principal amount of $150.0 million at a weighted average effective yield of 3.5%. As of June 30, 2023, the fair value of the October 2026 Notes was $127.8 million. This is a Level 3 fair value measurement under ASC 820 based on a valuation model using a discounted cash flow analysis. The Company recognized interest expense related to the October 2026 Notes, including amortization of deferred issuance costs, of $1.5 million and $1.4 million for the three months ended June 30, 2023 and 2022, respectively. For each of the three months ended June 30, 2023 and 2022, average borrowings were $150.0 million. The indenture governing the October 2026 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the October 2026 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Exchange Act. These covenants are subject to important limitations and exceptions that are described in the indenture and the fourth supplemental indenture relating to the October 2026 Notes. In addition, holders of the October 2026 Notes can require the Company to repurchase some or all of the October 2026 Notes at a purchase price equal to 100% of their principal amount, plus accrued and unpaid interest to, but not including, the repurchase date upon the occurrence of a “Change of Control Repurchase Event,” as defined in the fourth supplemental indenture relating to the October 2026 Notes. August 2028 Notes In June 2023, the Company issued approximately $71.9 million in aggregate principal amount, including the underwriters' full exercise of their option to purchase an additional $9.4 million in aggregate principal amount to cover over-allotments, of 7.75% notes due 2028 (the "August 2028 Notes"). The August 2028 Notes mature on August 1, 2028 and may be redeemed in whole or in part at any time, or from time to time, at the Company’s option on or after August 1, 2025. The August 2028 Notes bear interest at a rate of 7.75% per year, payable quarterly on February 1, May 1, August 1 and November 1 of each year, beginning on August 1, 2023. The August 2028 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under Credit Facility and the SBA Debentures. The August 2028 Notes are listed on the Nasdaq Global Select Market under the trading symbol "CSWCZ." As of June 30, 2023, the carrying amount of the August 2028 Notes was $69.3 million on an aggregate principal amount of $71.9 million at a weighted average effective yield of 7.75%. As of June 30, 2023, the fair value of the August 2028 Notes was $72.3 million. The fair value is based on the closing price of the security on The Nasdaq Global Select Market, which is a Level 1 input under ASC 820. The Company recognized interest expense related to the August 2028 Notes, including amortization of deferred issuance costs, of $0.3 million for the three months ended June 30, 2023. Since the issuance of the August 2028 Notes on June 14, 2023 through June 30, 2023, average borrowings were $71.9 million. The indenture governing the August 2028 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the August 2028 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Exchange Act. These covenants are subject to important limitations and exceptions that are described in the indenture and the fifth supplemental indenture relating to the August 2028 Notes. SBA Debentures On April 20, 2021, SBIC I received a license from the SBA to operate as an SBIC under Section 301(c) of the Small Business Investment Act of 1958, as amended. The license allows SBIC I to obtain leverage by issuing SBA Debentures, subject to the issuance of a leverage commitment by the SBA. SBA Debentures are loans issued to an SBIC which have interest payable semi-annually and a ten-year maturity. The interest rate is fixed shortly after issuance at a market-driven spread over U.S. Treasury Notes with ten-year maturities. Interest on SBA Debentures is payable semi-annually on March 1 and September 1. Current statutes and regulations permit SBIC I to borrow up to $175 million in SBA Debentures with at least $87.5 million in regulatory capital (as defined in the SBA regulations). On May 25, 2021, SBIC I received a leverage commitment from the SBA in the amount of $40.0 million to be issued on or prior to September 30, 2025. On January 28, 2022, SBIC I received an additional leverage commitment in the amount of $40.0 million to be issued on or prior to September 30, 2026. On November 22, 2022, SBIC I received an additional leverage commitment in the amount of $50.0 million to be issued on or prior to September 30, 2027. As of June 30, 2023, SBIC I had regulatory capital of $65.0 million and leverageable capital of $65.0 million. As of June 30, 2023, SBIC I had a total leverage commitment from the SBA in the amount of $130.0 million, of which $5.0 million remains unused. The SBA may limit the amount that may be drawn each year under these commitments, and each issuance of leverage is conditioned on the Company’s full compliance, as determined by the SBA, with the terms and conditions set forth in the SBA regulations. As of June 30, 2023, the carrying amount of SBA Debentures was $121.4 million on an aggregate principal amount of $125.0 million. As of June 30, 2023, the fair value of the SBA Debentures was $117.8 million. The fair value of the SBA Debentures is estimated by discounting the remaining payments using current market rates for similar instruments and considering such factors as the legal maturity date and the ability of market participants to prepay the SBA Debentures, which are Level 3 inputs under ASC 820. The Company recognized interest expense and fees related to SBA Debentures of $1.4 million and $0.4 million for the three months ended June 30, 2023 and 2022, respectively. The weighted average interest rate on the SBA Debentures was 3.94% and 2.50% for the three months ended June 30, 2023 and 2022, respectively. For the three months ended June 30, 2023 and 2022, average borrowings were $123.7 million and $51.6 million, respectively. As of June 30, 2023, the Company's issued and outstanding SBA Debentures mature as follows (amounts in thousands):
Pooling Date (1) |  | Maturity Date |  | Fixed Interest Rate |  | June 30, 2023
9/22/2021 |  | 9/1/2031 |  | 1.575% |  | $ | 15,000 |
3/23/2022 |  | 3/1/2032 |  | 3.209% |  | 25,000 |
9/21/2022 |  | 9/1/2032 |  | 4.435% |  | 40,000 |
3/22/2023 |  | 3/1/2033 |  | 5.215% |  | 40,000 |
(2) |  | (2) |  | (2) |  | 5,000 |
|  |  |  |  |  | $ | 125,000 |
(1)The SBA has two scheduled pooling dates for SBA Debentures (in March and in September). Certain SBA Debentures funded during the reporting periods may not be pooled until the subsequent pooling date. (2)The Company issued $5.0 million in SBA Debentures that will pool in September 2023. Until the pooling date, the SBA Debentures bear interest at a fixed rate with a weighted-average interim interest rate of 5.66%. |  |  |
Alternative Reference Rates Economic Results Risk [Member] |  |  |  |
General Description of Registrant [Abstract] |  |  |  |
Risk [Text Block] | The alternative reference rates that have replaced LIBOR in our credit arrangements and other financial instruments may not yield the same or similar economic results as LIBOR over the life of such transactions. The London Interbank Offered Rate (“LIBOR”) is an index rate that historically was widely used in lending transactions and was a common reference rate for setting the floating interest rate on private loans. LIBOR was typically the reference rate used in floating-rate loans extended to our portfolio companies. The ICE Benchmark Administration (“IBA”) (the entity that is responsible for calculating LIBOR) ceased providing overnight, one, three, six and twelve months USD LIBOR tenors on June 30, 2023. In addition, the United Kingdom’s Financial Conduct Authority (“FCA”), which oversees the IBA, now prohibits entities supervised by the FCA from using LIBORs, including USD LIBOR, except in very limited circumstances. In the United States, the Secured Overnight Financing Rate (“SOFR”) is the preferred alternative rate for LIBOR. SOFR is a measure of the cost of borrowing cash overnight, collateralized by U.S. Treasury securities, and is based on directly observable U.S. Treasury-backed repurchase transactions. SOFR is published by the Federal Reserve Bank of New York each U.S. Government Securities Business Day, for transactions made on the immediately preceding U.S. Government Securities Business Day. Alternative reference rates that may replace LIBOR, including SOFR for USD transactions, may not yield the same or similar economic results as LIBOR over the lives of such transactions. Substantially all of our loans that referenced LIBOR have been amended to reference the forward-looking term rate published by CME Group Benchmark Administration Limited based on the secured overnight financing rate (“CME Term SOFR”). CME Term SOFR rates are forward-looking rates that are derived by compounding projected overnight SOFR rates over one, three, and six months taking into account the values of multiple consecutive, executed, one-month and three-month CME Group traded SOFR futures contracts and, in some cases, over-the-counter SOFR Overnight Indexed Swaps as an indicator of CME Term SOFR reference rate values. CME Term SOFR and the inputs on which it is based are derived from SOFR. Since CME Term SOFR is a relatively new market rate, there will likely be no established trading market for credit agreements or other financial instruments when they are issued, and an established market may never develop or may not be liquid. Market terms for instruments referencing CME Term SOFR rates may be lower than those of later-issued CME Term SOFR indexed instruments. Similarly, if CME Term SOFR does not prove to be widely used, the trading price of instruments referencing CME Term SOFR may be lower than those of instruments indexed to indices that are more widely used. |  |  |
January 2026 Notes [Member] |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt, Title [Text Block] | January 2026 Notes |  |  |
Long Term Debt, Structuring [Text Block] | In December 2020, the Company issued $75.0 million in aggregate principal amount of 4.50% Notes due 2026 (the "Existing January 2026 Notes"). The Existing January 2026 Notes were issued at par. In February 2021, the Company issued an additional $65.0 million in aggregate principal amount of the January 2026 Notes (the "Additional January 2026 Notes" together with the Existing January 2026 Notes, the "January 2026 Notes"). The Additional January 2026 Notes were issued at a price of 102.11% of the aggregate principal amount of the Additional January 2026 Notes, resulting in a yield-to-maturity of approximately 4.0% at issuance. The Additional January 2026 Notes are treated as a single series with the Existing January 2026 Notes under the indenture and have the same terms as the Existing January 2026 Notes. The January 2026 Notes mature on January 31, 2026 and may be redeemed in whole or in part at any time prior to October 31, 2025, at par plus a "make-whole" premium, and thereafter at par. The January 2026 Notes bear interest at a rate of 4.50% per year, payable semi-annually on January 31 and July 31 of each year. The January 2026 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under the Credit Facility and the SBA Debentures. As of June 30, 2023, the carrying amount of the January 2026 Notes was $139.1 million on an aggregate principal amount of $140.0 million at a weighted average effective yield of 4.46%. As of June 30, 2023, the fair value of the January 2026 Notes was $118.4 million. This is a Level 3 fair value measurement under ASC 820 based on a valuation model using a discounted cash flow analysis. The Company recognized interest expense related to the January 2026 Notes, including amortization of deferred issuance costs, of $1.7 million for each of the three months ended June 30, 2023 and 2022. For each of the three months ended June 30, 2023 and 2022, average borrowings were $140.0 million. |  |  |
Long Term Debt, Dividends and Covenants [Text Block] | The indenture governing the January 2026 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the January 2026 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Securities Exchange Act of 1934, as amended (the "Exchange Act"). These covenants are subject to important limitations and exceptions that are described in the indenture and the third supplemental indenture relating to the January 2026 Notes. In addition, holders of the January 2026 Notes can require the Company to repurchase some or all of the January 2026 Notes at a purchase price equal to 100% of their principal amount, plus accrued and unpaid interest to, but not including, the repurchase date upon the occurrence of a “Change of Control Repurchase Event,” as defined in the third supplemental indenture relating to the January 2026 Notes. |  |  |
October 2026 Notes [Member] |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt, Title [Text Block] | October 2026 Notes |  |  |
Long Term Debt, Structuring [Text Block] | In August 2021, the Company issued $100.0 million in aggregate principal amount of 3.375% Notes due 2026 (the "Existing October 2026 Notes"). The Existing October 2026 Notes were issued at a price of 99.418% of the aggregate principal amount of the Existing October 2026 Notes, resulting in a yield-to-maturity of 3.5%. In November 2021, the Company issued an additional $50.0 million in aggregate principal amount of the October 2026 Notes (the "Additional October 2026 Notes" together with the Existing October 2026 Notes, the "October 2026 Notes"). The Additional October 2026 Notes were issued at a price of 99.993% of the aggregate principal amount, resulting in a yield-to-maturity of approximately 3.375% at issuance. The Additional October 2026 Notes are treated as a single series with the Existing October 2026 Notes under the indenture and have the same terms as the Existing October 2026 Notes. The October 2026 Notes mature on October 1, 2026 and may be redeemed in whole or in part at any time prior to July 1, 2026, at par plus a "make-whole" premium, and thereafter at par. The October 2026 Notes bear interest at a rate of 3.375% per year, payable semi-annually in arrears on April 1 and October 1 of each year. The October 2026 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under the Credit Facility and the SBA Debentures.As of June 30, 2023, the carrying amount of the October 2026 Notes was $147.4 million on an aggregate principal amount of $150.0 million at a weighted average effective yield of 3.5%. As of June 30, 2023, the fair value of the October 2026 Notes was $127.8 million. This is a Level 3 fair value measurement under ASC 820 based on a valuation model using a discounted cash flow analysis. The Company recognized interest expense related to the October 2026 Notes, including amortization of deferred issuance costs, of $1.5 million and $1.4 million for the three months ended June 30, 2023 and 2022, respectively. For each of the three months ended June 30, 2023 and 2022, average borrowings were $150.0 million. |  |  |
Long Term Debt, Dividends and Covenants [Text Block] | The indenture governing the October 2026 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the October 2026 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Exchange Act. These covenants are subject to important limitations and exceptions that are described in the indenture and the fourth supplemental indenture relating to the October 2026 Notes. In addition, holders of the October 2026 Notes can require the Company to repurchase some or all of the October 2026 Notes at a purchase price equal to 100% of their principal amount, plus accrued and unpaid interest to, but not including, the repurchase date upon the occurrence of a “Change of Control Repurchase Event,” as defined in the fourth supplemental indenture relating to the October 2026 Notes. |  |  |
August 2028 Notes [Member] |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt, Title [Text Block] | August 2028 Notes |  |  |
Long Term Debt, Structuring [Text Block] | In June 2023, the Company issued approximately $71.9 million in aggregate principal amount, including the underwriters' full exercise of their option to purchase an additional $9.4 million in aggregate principal amount to cover over-allotments, of 7.75% notes due 2028 (the "August 2028 Notes"). The August 2028 Notes mature on August 1, 2028 and may be redeemed in whole or in part at any time, or from time to time, at the Company’s option on or after August 1, 2025. The August 2028 Notes bear interest at a rate of 7.75% per year, payable quarterly on February 1, May 1, August 1 and November 1 of each year, beginning on August 1, 2023. The August 2028 Notes are the direct unsecured obligations of the Company, rank pari passu with the Company's other outstanding and future unsecured unsubordinated indebtedness and are effectively or structurally subordinated to all of the Company's existing and future secured indebtedness, including borrowings under Credit Facility and the SBA Debentures. The August 2028 Notes are listed on the Nasdaq Global Select Market under the trading symbol "CSWCZ." As of June 30, 2023, the carrying amount of the August 2028 Notes was $69.3 million on an aggregate principal amount of $71.9 million at a weighted average effective yield of 7.75%. As of June 30, 2023, the fair value of the August 2028 Notes was $72.3 million. The fair value is based on the closing price of the security on The Nasdaq Global Select Market, which is a Level 1 input under ASC 820. The Company recognized interest expense related to the August 2028 Notes, including amortization of deferred issuance costs, of $0.3 million for the three months ended June 30, 2023. Since the issuance of the August 2028 Notes on June 14, 2023 through June 30, 2023, average borrowings were $71.9 million. |  |  |
Long Term Debt, Dividends and Covenants [Text Block] | The indenture governing the August 2028 Notes contains certain covenants, including certain covenants requiring the Company to comply with Section 18(a)(1)(A) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, whether or not the Company continues to be subject to such provisions of the 1940 Act, but giving effect, in either case, to any exemptive relief granted to the Company by the SEC, to comply with Section 18(a)(1)(B) as modified by Section 61(a)(2) of the 1940 Act, or any successor provisions, after giving effect to any exemptive relief granted to the Company by the SEC and subject to certain other exceptions, and to provide financial information to the holders of the August 2028 Notes and the trustee under the indenture if the Company is no longer subject to the reporting requirements under the Exchange Act. These covenants are subject to important limitations and exceptions that are described in the indenture and the fifth supplemental indenture relating to the August 2028 Notes. |  |  |
Credit Facility [Member] |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt, Title [Text Block] | Credit Facility |  |  |
Long Term Debt, Structuring [Text Block] | In August 2016, CSWC entered into a senior secured revolving credit facility (the “Credit Facility”) to provide additional liquidity to support its investment and operational activities. On August 9, 2021, CSWC entered into the Second Amended and Restated Senior Secured Revolving Credit Agreement (as amended or otherwise modified from time to time, the "Credit Agreement"). Prior to the Credit Agreement, (1) borrowings under the Credit Facility accrued interest on a per annum basis at a rate equal to the applicable LIBOR rate plus 2.50% with no LIBOR floor, and (2) the total borrowing capacity was $340 million with commitments from a diversified group of eleven lenders. The Credit Agreement (1) decreased the total borrowing capacity under the Credit Facility to $335 million with commitments from a diversified group of ten lenders, (2) reduced the interest rate on borrowings to LIBOR plus 2.15% with no LIBOR floor and removed conditions related thereto as previously set forth in the Amended and Restated Senior Secured Revolving Credit Agreement, and (3) extended the end of the Credit Facility's revolver period from December 21, 2022 to August 9, 2025 and extended the final maturity from December 21, 2023 to August 9, 2026. The Credit Agreement also modified certain covenants in the Credit Facility, including, among other things, to increase the minimum obligors’ net worth test from $180 million to $200 million. The Credit Facility contains an accordion feature that allows CSWC to increase the total commitments under the Credit Facility up to $400 million from new and existing lenders on the same terms and conditions as the existing commitments. On May 11, 2022, CSWC entered into Amendment No. 2 (the "Amendment") to the Credit Agreement. The Amendment changed the benchmark interest rate from LIBOR to Adjusted Term SOFR. In addition, on May 11, 2022, CSWC entered into an Incremental Commitment Agreement, pursuant to which the total commitments under the Credit Agreement increased from $335 million to $380 million. On November 16, 2022, CSWC entered into an Incremental Assumption Agreement that increased the total commitments of the Credit Agreement by $20 million, which increased total commitments from $380 million to $400 million. The $20 million increase was provided by one existing lender and one new lender, bringing the total bank syndicate to eleven participants. CSWC pays unused commitment fees of 0.50% to 1.00% per annum, based on utilization, on the unused lender commitments under the Credit Facility. The Credit Facility is secured by (1) substantially all of the present and future property and assets of the Company and the guarantors and (2) 100% of the equity interests in the Company’s wholly-owned subsidiary. As of June 30, 2023, substantially all of the Company’s assets were pledged as collateral for the Credit Facility, except for assets held in SBIC I. At June 30, 2023, CSWC had $195.0 million in borrowings outstanding under the Credit Facility. CSWC recognized interest expense related to the Credit Facility, including unused commitment fees and amortization of deferred loan costs, of $4.9 million and $1.9 million for the three months ended June 30, 2023 and 2022, respectively. The weighted average interest rate on the Credit Facility was 7.36% and 3.16% for the three months ended June 30, 2023 and 2022, respectively. Average borrowings for the three months ended June 30, 2023 and 2022 were $239.7 million and $182.9 million, respectively. As of June 30, 2023 and 2022, CSWC was in compliance with all financial covenants under the Credit Agreement. |  |  |
Long Term Debt, Dividends and Covenants [Text Block] | The Credit Facility contains certain affirmative and negative covenants, including but not limited to: (1) certain reporting requirements, (2) maintaining RIC and BDC status, (3) maintaining a minimum senior coverage ratio of 2 to 1, (4) maintaining a minimum shareholders’ equity, (5) maintaining a minimum consolidated net worth, (6) maintaining a regulatory asset coverage of not less than 150%, (7) maintaining an interest coverage ratio of at least 2.25 to 1.0, and (8) at any time the outstanding advances exceed 90% of the borrowing base, maintaining a minimum liquidity of not less than 10% of the covered debt amount. The Credit Agreement also contains customary events of default, including, without limitation, nonpayment, misrepresentation of representations and warranties in a material respect, breach of covenant, bankruptcy, and change of control, with customary cure and notice provisions. If the Company defaults on its obligations under the Credit Agreement, the lenders may have the right to foreclose upon and sell, or otherwise transfer, the collateral subject to their security interests. |  |  |
SBA Debentures [Member] |  |  |  |
Capital Stock, Long-Term Debt, and Other Securities [Abstract] |  |  |  |
Long Term Debt, Title [Text Block] | SBA Debentures |  |  |
Long Term Debt, Structuring [Text Block] | On April 20, 2021, SBIC I received a license from the SBA to operate as an SBIC under Section 301(c) of the Small Business Investment Act of 1958, as amended. The license allows SBIC I to obtain leverage by issuing SBA Debentures, subject to the issuance of a leverage commitment by the SBA. SBA Debentures are loans issued to an SBIC which have interest payable semi-annually and a ten-year maturity. The interest rate is fixed shortly after issuance at a market-driven spread over U.S. Treasury Notes with ten-year maturities. Interest on SBA Debentures is payable semi-annually on March 1 and September 1. Current statutes and regulations permit SBIC I to borrow up to $175 million in SBA Debentures with at least $87.5 million in regulatory capital (as defined in the SBA regulations). On May 25, 2021, SBIC I received a leverage commitment from the SBA in the amount of $40.0 million to be issued on or prior to September 30, 2025. On January 28, 2022, SBIC I received an additional leverage commitment in the amount of $40.0 million to be issued on or prior to September 30, 2026. On November 22, 2022, SBIC I received an additional leverage commitment in the amount of $50.0 million to be issued on or prior to September 30, 2027. As of June 30, 2023, SBIC I had regulatory capital of $65.0 million and leverageable capital of $65.0 million. As of June 30, 2023, SBIC I had a total leverage commitment from the SBA in the amount of $130.0 million, of which $5.0 million remains unused. The SBA may limit the amount that may be drawn each year under these commitments, and each issuance of leverage is conditioned on the Company’s full compliance, as determined by the SBA, with the terms and conditions set forth in the SBA regulations. As of June 30, 2023, the carrying amount of SBA Debentures was $121.4 million on an aggregate principal amount of $125.0 million. As of June 30, 2023, the fair value of the SBA Debentures was $117.8 million. The fair value of the SBA Debentures is estimated by discounting the remaining payments using current market rates for similar instruments and considering such factors as the legal maturity date and the ability of market participants to prepay the SBA Debentures, which are Level 3 inputs under ASC 820. The Company recognized interest expense and fees related to SBA Debentures of $1.4 million and $0.4 million for the three months ended June 30, 2023 and 2022, respectively. The weighted average interest rate on the SBA Debentures was 3.94% and 2.50% for the three months ended June 30, 2023 and 2022, respectively. For the three months ended June 30, 2023 and 2022, average borrowings were $123.7 million and $51.6 million, respectively. As of June 30, 2023, the Company's issued and outstanding SBA Debentures mature as follows (amounts in thousands):
Pooling Date (1) |  | Maturity Date |  | Fixed Interest Rate |  | June 30, 2023
9/22/2021 |  | 9/1/2031 |  | 1.575% |  | $ | 15,000 |
3/23/2022 |  | 3/1/2032 |  | 3.209% |  | 25,000 |
9/21/2022 |  | 9/1/2032 |  | 4.435% |  | 40,000 |
3/22/2023 |  | 3/1/2033 |  | 5.215% |  | 40,000 |
(2) |  | (2) |  | (2) |  | 5,000 |
|  |  |  |  |  | $ | 125,000 |
(1)The SBA has two scheduled pooling dates for SBA Debentures (in March and in September). Certain SBA Debentures funded during the reporting periods may not be pooled until the subsequent pooling date. (2)The Company issued $5.0 million in SBA Debentures that will pool in September 2023. Until the pooling date, the SBA Debentures bear interest at a fixed rate with a weighted-average interim interest rate of 5.66%. |  |  |

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