I want my daughters returned to me after they were taken to another state by their father.

10 Years ago my daughters were taken out of state. I just recently found them on face book and they want to come back to me. I have not told them it is an option for fear of getting their hopes up and I can't get them. One major point there was never a custody order set. So technique, if memory serves me right, custody is only relavent if they are in his physical custody. I can go pick them up and bring them home and file a custody hearing in my home state. Am I correct? Would this be an unwise choice and the courts would frown upon it. I want to have them. Another important point, they are 13, 15, 17 years old. So we are not talking about little kids and they would wiling come with me. I would not be "kidnapping" them. Any help would be appreciated. They live in WI and I live in PA. I feel the need to add that so I can get the most accurate answer possible. Further more, neither of us abuses them, uses drugs, or alcohol.