The instructions linked by RobertB4444 state that "taxpayers may be required to submit documentation". It does not denote when they must submit documentation. As @aaustinf notes, the instructions for form 104 indicate claims over $5000 need documentation. This is still a bit unclear as it does not state if that is a single donation over $5000, or total donations over $5000.
@RobertB4444
@aaustinf
