JetBrains has a new application called the Toolbox App which quickly and easily installs any JetBrains software you want, assuming you have the license. It also manages your login once to apply across all JetBrains software, a very useful feature.
To use it, download the tar.gz file here, then extract it and run the included executable jetbrains-toolbox.
Then sign in, and press install next to IntelliJ IDEA:
If you want to move the executable to /usr/bin/
feel free, however it works fine out of the box wherever you extract it to.
This will also make the appropriate desktop entries upon install.