Every third day to do the same workout does not sound unreasonable at all. However, you need to listen to your body. As a general rule when it comes to recovery you should follow periods of heavy lifting with an equal amount of time of light to no training. However, this is only a general rule and everybody is different. So, while it would seem that every third day will not lead to over-training, you will want to keep an eye out for what is referred to as accommodation. Accommodation is where your muscles become used to the training program you are doing and you plateau. So, if you find your gains slow or stop it is more likely that your muscles have accommodated and less likely that you are over training.