There are plenty of tools out there for CNVs detection from WES data! In addition to VarScan, cited by 2nelly, you can also try with:
I also suggest you to read this article.
I worked on CNVs detection in the recent past, and I developed a simple wrapper for a CNV simulator developed by NabaviLab that I found a little bit complicated in the first place. (WARNING : Simulation is slow!)
You can maybe simulate reads similar to you real data (similar depth of coverage, similar balancing in term of amplifications and deletions given what you expect to find, etc) with CNVs inserted in known place and then test the different tools to find which one suits better your task!
Hope this helps!