Idaho Code § 50-311
Cities are empowered to: create, open, widen or extend any street, avenue, alley or lane, annul, vacate or discontinue the same whenever deemed expedient for the public good; to take private property for such purposes when deemed necessary, or for the purpose of giving right of way or other privileges to railroad companies, or for the purpose of erecting malls or commons; provided, however, that in all cases the city shall make adequate compensation therefor to the person or persons whose property shall be taken or injured thereby. The taking of property shall be as provided in title 7, chapter 7, Idaho Code. The amount of damages resulting from the vacation of any street, avenue, alley or lane shall be determined, under such terms and conditions as may be provided by the city council. Provided further that whenever any street, avenue, alley or lane shall be vacated, the same shall revert to the owner of the adjacent real estate, one-half (1/2) on each side thereof, or as the city council deems in the best interests of the adjoining properties, but the right of way, easements and franchise rights of any lot owner or public utility shall not be impaired thereby. In cities of fifty thousand (50,000) population or more in which a dedicated alley has not been used as an alley for a period of fifty (50) years [such alley] shall revert to the owner of the adjacent real estate, one-half (1/2) on each side thereof, by operation of the law, but the existing rights of way, easements and franchise rights of any lot owner or public utility shall not be impaired thereby.
Idaho Code § 50-311