Idaho Code § 31-5701
The form of government provided in this chapter shall consist of the consolidation of one (1) or more county offices, other than the office of county commissioner, in two (2) or more counties, with all other characteristics of the form of government existing in each participating county to continue unchanged. No petition or resolution proposing a consolidation of offices between or among counties shall propose any other optional form of county government or any other changes in the existing form of government in any of the counties proposing to consolidate offices; except that the question of adopting another optional form of government in a participating county as proposed by a separate petition or resolution may be submitted at the same general election by the governing body of that county, as provided in section 31-5005, Idaho Code. The petition or resolution shall identify each of the counties participating in the consolidation.
Idaho Code § 31-5701