weedwacker, in statutes, paragraph 2 bullet (e)
"School" means a private or public elementary or secondary school.
as it is not a secondary(highschool) or elementary(1-8) then a college campus can not be considered a school under Idaho law and as part of Idaho law, with the exception of government buildings and schools(already defined), no sign that says 'no weapons allowed' carries the weight of law and since Idaho is an open carry state it is legal for students to carry both concealed(with permit) and non concealed firearms on campus. the campus may choose to have you evicted from the property as a trespasser however a student with active ID can not be considered a trespasser so regardless of how you want to look at it,
it is legal and nobody can stop you without facing a lawsuit.