Abstract: A transaction fraud detection system allows for the processing of documents such as checks in a way that reduces the possibility of fraud. The transaction fraud detection system provides customer enrollment and check enrollment functionality. It applies rules to data collected using the customer enrollment, the check enrollment, and possibly other data sources to determine a risk associated with a transaction, which may include generating a score. The applied rules may be customized via risk modeling functionality. For example, an administrator may be able to custom-select the types of rules to apply, the weighting or value given to any given rule, etc. The risk modeling may be at least partially automated, and may involve self-learning aspects that allow the risk modeling and/or application of rules to be at least partially based on past transactions.