Stephen Madison added nine points, 12 rebounds and five assists for Idaho (5-4).
Joe Burton had 15 points and eight rebounds for Oregon State (6-2), playing two days after the death of Beavers football player Fred Thompson after a pick-up basketball game on campus.
The Vandals led 35-24 at halftime and a Djim Bandoumel basket gave Idaho a 44-28 lead with 17:06 remaining. Oregon State then went on an 8-2 run—capped by a Roberto Nelson 3-pointer—to close within 10 points.
Idaho then scored seven straight points, with Connor Hill’s 3-pointer making it 53-36 with 10:55 left. The Vandals later led by as many as 18 points, and Oregon State got no closer than 11 after that.