Idaho Code § 68-406
All guardians, trustees and other fiduciaries may legally invest any funds administered by them in any life, endowment or annuity contracts issued by any legal reserve life insurance company authorized to do business in the state of Idaho, it being the purpose of this act to authorize any private person, bank, trust company or other institution acting as guardian, trustee or fiduciary to invest funds coming into their possession or under their control as such guardian, trustee or fiduciary in any life, endowment, or annuity contracts issued by any legal reserve insurance company authorized to do business in the state of Idaho, when, in their opinion, it will be for the best interests of their wards or trust estate, provided, however, that whenever an order of the probate court or other court has been heretofore required by law for the investment of any funds being administered by such guardian, trustee or other fiduciary, then such order shall be required in cases of investment of funds under this act.
Idaho Code § 68-406