Idaho Code § 15-2-104
Any person who fails to survive the decedent by one hundred twenty (120) hours is deemed to have predeceased the decedent for purposes of homestead allowance, exempt property and intestate succession, and the decedent's heirs are determined accordingly. If the time of death of the decedent or of the person who would otherwise be an heir, or the times of death of both, cannot be determined, and it cannot be established that the person who would otherwise be an heir has survived the decedent by one hundred twenty (120) hours, it is deemed that the person failed to survive for the required period. This section is not to be applied where its application would result in a taking of intestate estate by the state under section 15-2-105 of this Part.
Idaho Code § 15-2-104