Crawdad Regulations

I would like someone to clarify for me the exact regulations on fishing for crawdad/crayfish in Idaho. My understanding is that you only need a regular fishing licence unless you have over five(5) traps. And that if you have over five traps then you need some type of commercial licence. Also to my understanding, there is no number limit or size restrictions on crawdad in Idaho. Is all that I have said correct and are there any other regulations? Also, how much does one of those commercial licences cost?