Vanessa, I don’t believe IDEA offers a group fitness certification. Could you be referring to the American Council on Exercise?
If you are referring to the American Council on Exercise, I can tell you now that most American credentials are not recognized in Australia and some not all European nations. The only American credential that I know is recognized is the NASM credential and you would need to take it through Performance Training Solutions who is an approved training provider in the UK.
Having lived in Europe and experienced what it takes for one’s credentials to be recognized ab, I can tell you that you will need to sit for and pass for a group fitness certification has been approved by the Registry of Exercises professionals in the country where you want to work. You can learn more about this by visiting www.exerciseregister.org. On the left hand side of the webpage you will see a link that reads “worldwide picture” click on that link in order to learn more regarding what you need to do to work abroad in the countries you mention in your question.
I wish you the best.