BajaPete reminded me about this:
I thought you may like to know that effective immediately, there is a new permit required to launch or operate vessels on Idaho waterways.
I have talked to Idaho Dept of Licensing and Idaho Dept of Parks and Recreation, you must purchase item online or by mail.
The following link will give you the details.
Failure to have this sticker is a $57 fine! Even out of state boats must have it, and you cannot purchase locally, only online or by mail.