Where there are no approved depositories in the depositing unit, or where the money in the treasury exceeds the amount which the designated depositories in the depositing unit are willing to accept, the said excess moneys may be deposited in financial institutions outside of the depositing unit, but within the state of Idaho, which may be designated by the supervising board under the same conditions and subject to the same requirements as if in the depositing unit, and where the money in the treasury exceeds the amount which all designated depositories in the state are willing to accept, such excess may in that event and not otherwise, be deposited in banks outside the state, which banks shall be designated by the supervising board under the same conditions and subject to the same requirements as for designated depositories in the depositing unit.