Idaho Code § 32-801

A divorce may be granted for the cause of permanent insanity of the spouse: provided, that no divorce shall be granted under the provisions of this chapter unless such insane person shall have been duly and regularly confined in an insane asylum of this state, or of a sister state or territory, or foreign country for at least three (3) years next preceding the commencement of the action for divorce, nor unless it shall appear to the court that such insanity is permanent and incurable.