How to insert contents of another file?

Let's say I'm editing a file and I want to insert the complete contents of another file at the current location in my edit window. Is there a built-in way to do that?

With vi or vim I could use :r to read a file below the current location (doesn't work with the Vim Emulator in IDEA - I tried).

With emacs I can C-x C-i to Insert File.

I can't seem to find anything equivalent in IDEA.

I would prefer not to have to open the other file (it's in another project, another language, etc...).

I know I can open the file somewhere else, copy the contents, and paste it into my buffer. But this is a basic operation that I've found in every other editor/IDE I use.