diff --git a/src/main/java/envoy/data/Attachment.java b/src/main/java/envoy/data/Attachment.java
index 7b8d397..bfc496a 100644
--- a/src/main/java/envoy/data/Attachment.java
+++ b/src/main/java/envoy/data/Attachment.java
@@ -35,7 +35,14 @@ public class Attachment implements Serializable {
 		 * 
 		 * @since Envoy Common v0.1-beta
 		 */
-		VOICE
+		VOICE,
+
+		/**
+		 * This attachment type denotes a document.
+		 *
+		 * @since Envoy Common v0.1-beta
+		 */
+		DOCUMENT
 	}
 
 	private final byte[]			data;