Section 63-3610, Idaho Code
Every auctioneer, agent, broker, distributor and factor acting for a principal, or entrusted with any bill of lading, custom house permit for delivery or any tangible personal property or entrusted with possession of any tangible personal property for the purpose of sale, collects and remits sales tax on those sales. This is true even if the principal or owner of the property would not have had a requirement to do so.
Idaho Admin. Code r. 35.01.02.020