Idaho Code § 50-2108
From and after the date of filing an abstract of results of election of officials with the secretary of state, such consolidation shall be deemed to be completed, and such cities shall be deemed to be consolidated into a new corporation under the name of the corporation of the greater or greatest population, and thereupon such new corporation shall be governed in the name of and under the laws and ordinances applicable to such larger or largest city. The officials elected at a special election shall be immediately entitled to enter upon the duties of their respective offices, upon qualifying in accordance with law, and shall hold said offices respectively only until the next general city election in such newly consolidated city, and until their successors are elected and qualified. At the first general city election following the effective date of such newly consolidated city, one-half (1/2) of the city council shall be elected for two (2) year terms, and one-half (1/2) shall be elected for four (4) year terms. The mayor, at such first general city election, shall be elected for a four (4) year term.
Idaho Code § 50-2108