How to decompile to java files intellij idea

IDEA has a great built-in feature - decompiler. It works great.I can copy source code, but I cannot find option to extract all decompiled java classes to java files.
This project has a lot of java classes and packages, so I will be to long to copy this manually.
Does anyone know how to extract to java source files. Thx

As of August 2017 and IntelliJ V2017.2, the accepted answer does not seem to be entirely accurate anymore: there is no fernflower.jar to use.

The jar file is called java-decompiler.jar and does not include a main manifest... Instead you can use the following command (from a Mac install):

java -cp "/Applications/IntelliJ IDEA.app/Contents/plugins/java-decompiler/lib/java-decompiler.jar" org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler

(you will get the wrong Usage command, but it does work).

To use the IntelliJ Java decompiler from the command line for a jar package follow the instructions provided here: https://github.com/JetBrains/intellij-community/tree/master/plugins/java-decompiler/engine