Idaho Code § 70-1616
A port district may lease all real and personal property owned or controlled by it, and/or improvements thereon, upon such terms as the port commission deems proper; provided, that no lease shall be for a period longer than fifty (50) years, and each lease of real property shall be secured by a bond, with surety satisfactory to the port commission, or by such other rental insurance or financial guaranty as may be deemed sufficient by the port commission, conditioned to perform the terms of such lease, including the payment in lieu of taxes provided for in this act; provided further, that where the property is held by the district under lease from the United States government or any agency, instrumentality or political subdivision thereof, the port commission may sublease said property, with option for extensions, up to the total term and extensions thereof permitted by such United States lease, but in any event not to exceed ninety (90) years; provided further, that in a lease, the term of which exceeds five (5) years, and when at the option of the port commission it is so stipulated in the lease, the commission shall accept, with surety satisfactory to it, a bond or other such rental insurance or financial guaranty satisfactory to the port commission, conditioned to perform the terms of the lease for some part of the term, in no event less than five (5) years unless the remainder of the unexpired term is less than five (5) years, in which case for the full remainder and in every such case the commission shall require of the lessee, another or other like bond or other rental insurance or financial guaranty to be delivered within two (2) years, and not less than one (1) year prior to the expiration of the period covered by the existing bond, covering an additional part of the term in accordance with the foregoing provisions in respect to the original bond, and so on until the end of the term so that there will always be in force a bond or other rental insurance or financial guaranty securing the performance of the lease, and the penalty in each bond or other rental insurance or financial guaranty shall be not less than the rental for one-half (1/2) the period covered thereby, but no bond or other rental insurance or financial guaranty shall be construed to secure the furnishing of any other bond or other rental insurance or financial guaranty.
Idaho Code § 70-1616