Boatwright tied his career-high with five 3-pointers on eight attempts and scored 11 of his points in the second half to help USC (7-2) break open a game that was tied at halftime.
''I'm just trying to help my team any way possible,'' Boatwright said. ''The coaches have been instilling confidence in me all season, and I'm trying to be an all-around player.''
Boatwright is now averaging 12.1 points per game on the season, third-most on the team, and leads the Trojans with 20 made 3-pointers.
''When Bennie's feet are set and he's taking open shots, he's as good as I've seen,'' USC coach Andy Enfield said. ''Tonight he played well in all aspects.''
With Boatwright leading the way, the Trojans outscored the Vandals 44-25 in the second half.
''Our plan was to give Boatwright a few looks and focus on guarding other guys, and then adjust if he makes them,'' Idaho coach Don Verlin said. ''We probably made that adjustment a little too late.''
Nikola Jovanovic added 11 points and eight rebounds, and Julian Jacobs scored 11 points for USC. The Trojans made 12 3-pointers, their fifth time this season making at least 10. Reinhardt made four 3s and Jordan McLaughlin hit a pair.
''Shooting 3s isn't necessarily something we plan on,'' Reinhardt said. ''We're just taking what the defense gives us.''
''We have to take care of the ball better,'' Verlin said. ''I don't think they pressured us that much, we were just sloppy.''
The score was tied 30-all at halftime before USC pulled away.
Reinhardt and Boatwright opened the second half with back-to-back 3-pointers - with Reinhardt assisting on Boatwright's bucket - to start a 9-3 run that put USC in front for good.
Boatwright hit another 3-pointer to give them a 50-42 edge, and Jovanovic followed with a layup to give USC its first double-digit lead with just under 10 minutes to go.
''The way we started the second half, that's USC basketball,'' Boatwright said. ''Our coaches got into us at halftime for not playing hard enough and thinking we were too good. We remembered we have to come out and outwork everybody.''
Reinhardt's third 3-pointer and a layup by Jacobs made it 64-47 with five minutes to go and USC remained ahead by double-digits the rest of the way.
The Trojans shot 53.6 percent in the second half after shooting just 39.3 percent in the first.
Idaho: The Vandals have five new starters this season. ... They lost despite winning the rebounding battle 39-27. ... Five of Idaho's last seven games have been decided by 10 points or less.
USC: The Trojans improved to 11-1 all-time against Idaho. The teams' last meeting came in 1976. ... They scored 27 points off turnovers and had 11 fast-break points. . USC has won two straight after suffering its first two losses last week.
Idaho hosts Washington State on Thursday.
USC hosts Yale on Sunday.
NOT SO FREE
USC's shot just 10 of 18 from the free-throw line, continuing a season-long issue. Including their performance against Idaho, the Trojans are shooting 67 percent from the charity stripe this season.
J-MAC'S NEW MASK
Jordan McLaughlin was fitted for a new clear protective mask in advance of Idaho after struggling the previous two games wearing a different one.
McLaughlin broke his nose on Nov. 27 against Xavier. He scored only five points in the two games following the injury, down from his season average of 19.2 points per game.
He didn't shoot much better with the new mask, scoring only six points on 2-of-7 shooting from the field.