v2.4.0.6
Document And Entity Information (USD $)
In Thousands, except Share data, unless otherwise specified
9 Months Ended
Dec. 31, 2010
Feb. 08, 2012
Sep. 30, 2010
Entity Registrant Name CAPITAL SOUTHWEST CORP    
Entity Central Index Key 0000017313    
Current Fiscal Year End Date --03-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 250,728,582
Entity Common Stock, Shares Outstanding   3,754,538  
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q3    
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Dec. 31, 2011