Okay. TECHNICALLY what the dealer's employee did is not THEFT per se in Delaware. Delaware is one of the few states that still has screwed up, antiquated laws in some respects, and this is one.
What the employee did was commit the crime of Unauthorized Use of a Vehicle. Regardless of the amount of damage caused, it is a misdemeanor in Delaware.
DEL CODE ยง 853 : Delaware Code - Section 853: UNAUTHORIZED USE OF A VEHICLE; CLASS A MISDEMEANOR
A person is guilty of unauthorized use of a vehicle when:
(1) Knowing that the person does not have the consent of the owner the person takes, operates, exercises control over, rides in or otherwise uses a vehicle;
(2) Having custody of a vehicle pursuant to an agreement between the person or another and the owner thereof whereby the person or another is to perform for compensation a specific service for the owner involving the maintenance, repair or use of the vehicle, the person intentionally uses or operates it, without the consent of the owner, for the person's own purposes in a manner constituting a gross deviation from the agreed purpose;
In Arizona, and most states, that would be a felony.
So, technically, he could not be charged with theft because the theft and the auto theft statutes in Delaware require intent to permanently deprive the owner of his vehicle. This deadbeat was just joy-riding. No theft.
But, he still committed a crime ~ Unauthorized Use of a Vehicle.