Sections 63-3612, 63-3613, 63-3621, Idaho Code
When tangible personal property is located within the state of Idaho at the time of sale and is delivered within the state of Idaho, such sale is taxable irrespective of where the parties to the contract of sale are located and where the contract was made or accepted or the funds paid. Example: A Washington-based interstate trucking firm hires an Idaho repair facility to install parts on a disabled truck. The trucking firm takes delivery of the repaired vehicle in Idaho. The sale of the parts is subject to Idaho sales tax.
Idaho Admin. Code r. 35.01.02.069