A system for processing documents is provided for use in remittance processing of bulk mail. An extraction unit opens envelopes and extracts the envelope contents, typically in the form of a pair of documents such as an invoice stub and an accompanying check. The extraction unit discards the opened envelopes and feeds the pair of documents in parallel disposition to a document sorting apparatus. The paired, parallel documents are conveyed through a document shifter in the form of nip rollers wherein one document of each pair is at least partially shifted relative to the other document of the pair to expose at least a portion of the covered document to an operator. The documents are then conveyed to a viewing area where the operator visually inspects each pair of documents and manually designates a selected path of movement using a manual input device. From the viewing area, the documents are conveyed to a staging area where the documents may be redirected along another path of movement by operator use of the manual input device. From the staging area, the pairs of documents are conveyed to selected bins in response to the manual inputs by the operator.