In majority of cases the overseas market allows foreign pilots to be employed on an "on needed" basis if they have a shortage of qualified applicants. So tons of US pilots flying on long term contracts in Asia, Africa and the Middle-East. Obviously you are a contractor and will be replaced as soon as you are no longer needed and locals will almost always be favored. You have no real seniority or job protection and you are only as good as your last flight. As long as you remember that you should be fine. There are many expats who have made a good living flying contract overseas with all its ups and downs.