Idaho Code § 63-402
All property belonging to any person owning, operating or constructing any public utility or railroad, wholly or partly within this state, not included within the meaning of the term "operating property" as defined in this title, namely, property not reasonably necessary for the maintenance and operation of such public utility or railroad, including land or buildings rented by a company or corporation as lessee which is used as or in connection with its business, such as business offices, warehouses, service centers, moorage grounds or docks, vacant lots and tracts of land, and lots and tracts of land with the buildings thereon not used or intended to be used in the operation of such public utility or railroad, also tenement and resident property, except section houses, also hotels and eating houses, not situated adjacent to the main track of any such railroad, shall be assessed by the assessor of the county wherein the same is situated.
Idaho Code § 63-402