No, detailing, although it may feel "stressful" on your muscles is not a work out. The amount of washing and polishing and hand waxing that must be done to tear enough muscle tissue to induce "growth" is way too great.
Think of it like this, take cyclists for example, most of them have pretty well built calves, and that is strictly due to pedaling hard for long amounts of time (pedaling actually isolates the calf muscle) but any action in detailing doesnt isolate any muscle to great extent.
Now to build good calves (for those that have the ability to do so) as a cyclists it would take years of cycling alone. For those who workout, they can build the same amount of muscle and size (or more) in a few months of working out their calves with resistance training.
Bottom line, resistance training is how you build muscle efficiently.