You can. It's only the first time when using the IDE that it requires a connection to the internet to download some additional stuff. After that it can work without an internet connection.
Note that offline does not necessarily mean that there is no internet connection; it can also be an connection between two processes on a PC.
Please follow the instructions in this post (Arduino 2.0.3 stuck on loading screen - #2 by ptillisch) and post the results here.
I probably can't help you further but I think that it will shine some light on the issue.