Idaho Code § 67-5102
Additional state jurisdiction in criminal and civil causes of action may be extended to particular reservations or Indian country with the consent of the governing body of the tribe occupying the Indian country effected [affected] by the assumption of such additional jurisdiction. This may be achieved by negotiation with the tribe or by unilateral action by the tribe. In every case the extent of such additional jurisdiction shall be determined by a resolution of the tribal governing body and become effective upon the tribe's transmittal of the resolution to the attorney general of the state of Idaho. Such resolution may effectively accept jurisdiction as to any particular field of criminal or civil jurisdiction. All state jurisdiction extended by virtue of this act shall be concurrent (and not exclusive) with jurisdiction in the same matters existing in the tribes or the federal government.
Idaho Code § 67-5102