The Vandals (16-17) will play in the WAC finals Saturday. Mike Scott had 14 points and Connor Hill added 12.
Utah Valley (20-11) was led by Mitch Bruneel with 18 points. Holton Hunsaker had 14 of his 15 points in the first half.
Idaho used an 8-0 run in the second half to push their lead to 10, but the Wolverines climbed back within one with 4:04 remaining. The Vandals responded as Madison hit a jumper, Hill drained a 3-pointer and Sekou Wiggs added a layup to make it 70-64.
Keawe Enos hit a 3-pointer and Hunsaker followed with a steal, but Bruneel couldn't connect on a 3-pointer with 10 seconds left. Madison hit two free throws to ice it.