Does University of Idaho (US) has good career prospectus for economic graduates?

It doesn't depend so much on the university as much as what you do at the university. Your grades, your relationships with your faculty, extra curricular activities, internships, grades, leadership positions - these are the things that will affect your employment prospects.

Not really. I tried grabbing the placement report from their website but could not find it. However, after my research, i have came to a conclusion that the placement opportunities are not very impressive at this university.