Scout and Jem have a very unique relationship with their father. He is a widower, and he works as a lawyer, so the time he spends with them is often in the evenings around and after dinner. As a result, Scout says he treats both her and Jem with "courteous detachment."
Atticus is very concerned with raising intelligent, open-minded, fair, moral, and respectful children. We see him emphasize these qualities in the conversations he has with the children throughout the book, but we also see him model this behavior for them. For example, he takes on the case of Tom Robinson because it is the moral thing to do, even if it is not the easy thing to do.
Atticus does not physically punish his children, which is unusual in the 1930s. Instead, he talks with them about what they did wrong. This shows that he respects his children and their points of view, but also that he feels his words can be more powerful than his hands.
Both Jem and Scout respect their father and love him. He is their only parent, and most significant role model.