The manual should state but I'm guessing 87 octane is just fine. The octane of the fuel determines its pre-ignition or pre-detonation rating, meaning the higher the compression of the motor, the higher octane you need to avoid pre-detonation of your air/fuel mixture.
Some folks think premium fuel means premium mileage, premium clean burning, or a whole host of other things...that are all wrong. Use the cheapest fuel your motor was designed for.