Idaho Code § 59-512
No employee in the several departments, employed at a fixed compensation, shall be paid for any extra service performed by such employee in the ordinary course of his employment, unless expressly authorized by law.
Whenever the public interest may be served thereby, an employee of any department, with the written approval of the employing director, may be permitted to accept additional employment by the same, or another department, in any educational program conducted under the supervision of the state board of education or the board of regents of the University of Idaho, when such additional employment is not in the ordinary course of the employment of such employee and will be performed in addition to, and beyond the hours of service required in the ordinary course of employment. The written approval of the employing director shall be filed with the secretary of the state board of examiners together with a statement that such additional employment is not in the course of the employee's employment, and will be performed in addition to the statutory hours of employment.
Idaho Code § 59-512