Idle temps are relatively unimportant. Maximum temperatures are the only thing that matters, at all. So long as the hardware is within it's tolerance specs, it doesn't matter whether it's by 2 degrees or twenty, so long as it doesn't exceed that. Idle temps are far less accurate across the board, doesn't matter if it's AMD, Intel, Nvidia, whoever, than the upper ranges anyhow. The only time idle temps matter is if they are clearly higher than averages for that component and the hardware is exceeding the thermal ceiling.
So if the idle temp is affecting the maximum temp, then it's a problem somewhere. If the maximum temp is within tolerance and remains there, doesn't really matter what the idle temp is.