Running a program on a server after logging off

At work we have a pretty powerful server on which we run computationally intensive programs. Many times, I want the programs I execute to continue running after I log off. This is how to do it:

screen -S blah  
Ctrl+a d  

I can now log off and go home. The program will continue executing safely.

The following day, I log back to the server and type:

screen -r blah  

I’m now back where I was.