A theft is completed when someone takes property belonging to another with the intent to deprive the owner of that property.  The intent is what controls.  If the state or victim can prove that a defendant took something with intent to keep it, then the charges can go forward, even if full restitution was made. However, the defendant who pays everything back in full may have a very good defense in that the repayment was evidence of intent not to deprive the owner of the property. In additon to a defense, the repayment can also serve as mitigation.  Many victims drop charges once they have received an apology and full compensation for their loss.