Idaho Code § 15-2-508
If after executing a will the testator is divorced or his marriage annulled, the divorce or annulment revokes any disposition or appointment of property made by the will to the former spouse, any provision conferring a general or special power of appointment on the former spouse, and any nomination of the former spouse as executor, trustee, conservator, or guardian, unless the will expressly provides otherwise. Property prevented from passing to a former spouse because of revocation by divorce or annulment passes as if the former spouse failed to survive the decedent, and other provisions conferring some power or office on the former spouse are interpreted as if the spouse failed to survive the decedent. If provisions are revoked solely by this section, they are revived by testator's remarriage to the former spouse. For purposes of this section, divorce or annulment means any divorce or annulment which would exclude the spouse as a surviving spouse within the meaning of subsection (b) of section 15-2-802 of this code. A decree of separation which does not terminate the status of husband and wife is not a divorce for purposes of this section. No change of circumstances other than as described in this section revokes a will.
Idaho Code § 15-2-508