    <SEC-DOCUMENT>0000017313-26-000029-index.html : 20260513
    <SEC-HEADER>0000017313-26-000029.hdr.sgml : 20260513
    <ACCEPTANCE-DATETIME>20260513161357
    ACCESSION NUMBER:		0000017313-26-000029
    CONFORMED SUBMISSION TYPE:	PRE 14A
    PUBLIC DOCUMENT COUNT:		19
    CONFORMED PERIOD OF REPORT:	20260722
    FILED AS OF DATE:		20260513
    DATE AS OF CHANGE:		20260513

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			CAPITAL SOUTHWEST CORP
    		CENTRAL INDEX KEY:			0000017313
    		ORGANIZATION NAME:
    		EIN:				751072796
    		STATE OF INCORPORATION:			TX
    		FISCAL YEAR END:			0331

    	FILING VALUES:
    		FORM TYPE:		PRE 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	814-00061
    		FILM NUMBER:		26973420

    	BUSINESS ADDRESS:
    		STREET 1:		8333 DOUGLAS AVE
    		STREET 2:		SUITE 1100
    		CITY:			DALLAS
    		STATE:			TX
    		ZIP:			75225
    		BUSINESS PHONE:		2142385700

    	MAIL ADDRESS:
    		STREET 1:		8333 DOUGLAS AVE
    		STREET 2:		SUITE 1100
    		CITY:			DALLAS
    		STATE:			TX
    		ZIP:			75225
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>PRE 14A
    <SEQUENCE>1
    <FILENAME>cswc-20260513.htm
    <DESCRIPTION>PRE 14A
    <TEXT>
    Document 1 - file: cswc-20260513.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>2
    <FILENAME>cswc-20260513.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 2 - file: cswc-20260513.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>cswc-20260513_g1.jpg
    <TEXT>
    Document 4 - file: cswc-20260513_g1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>cswc-20260513_g2.jpg
    <TEXT>
    Document 5 - file: cswc-20260513_g2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>cswc-20260513_g3.jpg
    <TEXT>
    Document 6 - file: cswc-20260513_g3.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>cswc-20260513_g4.jpg
    <TEXT>
    Document 7 - file: cswc-20260513_g4.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>cswc-20260513_g5.jpg
    <TEXT>
    Document 8 - file: cswc-20260513_g5.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>cswc-20260513_g6.jpg
    <TEXT>
    Document 9 - file: cswc-20260513_g6.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>cswc-20260513_g7.jpg
    <TEXT>
    Document 10 - file: cswc-20260513_g7.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>image_0.jpg
    <TEXT>
    Document 11 - file: image_0.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>14
    <FILENAME>R2.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 14 - file: R2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>15
    <FILENAME>R3.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 15 - file: R3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>16
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 16 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>17
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 17 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>19
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 19 - file: FilingSummary.html

    Document 19 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>21
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 21 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>22
    <FILENAME>0000017313-26-000029-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 22 - file: 0000017313-26-000029-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>23
    <FILENAME>cswc-20260513_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 23 - file: cswc-20260513_htm.html

    Document 23 - RAW XML: cswc-20260513_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>