COMMITMENTS (Details) (USD $)	Sep. 30, 2012
COMMITMENTS [Abstract]
Investment in portfolio companies, at maximum	$ 10,138,169
Number of portfolio companies, at maximum	9

The maximum number of portfolio companies the entity has agreed to invest in, subject to certain conditions.

No definition available.

Name:	cswc_NumberOfPortfolioCompaniesMaximum
Namespace Prefix:	cswc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant