judge and jury

So I was doing this translation job for a friend. Judge and Jury by James Patterson. As I stepped into higher chapters I realized why this novel hasn't been translated into Indonesian language yet. It is because inside there are a lot of idioms we are not familiar with.

For example poker. There are hole cards, ante, fold, raise, chip, pot, flush, low pairs, etc. Crime: union tampering, mistrial. Chess: opening, pawn break, etc. How am I supposed to translate all of them, making my readers who are not familiar with poker or chess or American justice system understand what's going on in the novel?

In the end I didn't translate most of those words but did add some explanation in other sentences... I feel bad... What should a translator do in such case?

Anyway, the story is about mafia in New York. First time I received it from the customer I was always on my toes until I finished reading it. If you have time you should read it. It put me on suspense!