You may also try tmux - it is a cleaner implementation of the same idea (terminal multiplexing), just as stable and has saner default keybindings (the main keyboard shortcut for screen is ctrl-a, which conflicts with emacs/bash ctrl-a (goto start of line), the main shorcut for tmux is ctrl-b, which is not used by emacs/bash by default).
1) run 'tmux'
2) launch your long running processing, etc.
3) press <ctrl-b-d> ### this detaches you from the tmux session (you can also just close the terminal window)
4) login again
5) in order to attach to the previous tmux session (with the long running process in it), run 'tmux att'
btw, you can attach from several *different* logins to the same session, which is usefull for sharing a session between several users (education, remote help, etc.)