Idaho Code § 50-1039
All bonds of the same issue shall, subject to the prior and superior rights of outstanding bonds, claims or obligations, have prior and paramount lien on the revenue of the works or rehabilitated existing electrical generating facilities for which said bonds have been issued, except that where provision is made in the ordinance authorizing any issue or series of bonds for the issuance of additional bonds in the future on a parity therewith pursuant to procedures or restrictions provided in such ordinance, additional bonds may be issued in the future on a parity with such issue or series in the manner so provided in such ordinance. All bonds of the same issue shall be equally and ratably secured without priority by reason of number, date of bonds, date of sale, date of execution, or date of delivery, by a lien on said revenue in accordance with the provisions of the Revenue Bond Act and the ordinance authorizing said bonds. Special facility bonds issued for airport facilities and air navigation facilities to be owned by private persons, associations or corporations and not by the political subdivision of the state or regional airport authority as defined by law shall be additionally secured by a deed of trust, mortgage or other lien on the facilities or other security or credit enhancement provisions.
Idaho Code § 50-1039