Idaho Code § 59-1382

Any city having a city system may elect to merge its city system with the employee system by the enactment of an ordinance declaring such intention; the provisions of section 50-1503, Idaho Code, and section 50-1524, Idaho Code, notwithstanding. Thereupon the board of the employee system may upon such terms as are set forth in a contract between the board and employer integrate the city system of the employer into the employee system.