Would I still be able to settle without involving my insurer even when the other party has involved his insurance company? What kind of document or agreement would I need to obtain to make sure that they won't be coming after me again?

My side mirroir collided with the side mirroir of an illegally parked car. the owner of the parked car and I exchanged driver license information but we didn't contact the police to fill up a report. His insurance company has contacted me regarding the accident. What should I do next? Should I resol...