rancher_environment: member documentation details

website/source/docs/providers/rancher/r/environment.html.md

@@ -40,7 +40,16 @@ The following arguments are supported:
 * `name` - (Required) The name of the environment.
 * `description` - (Optional) An environment description.
 * `orchestration` - (Optional) Must be one of **cattle**, **swarm**, **mesos** or **kubernetes**. Defaults to **cattle**.
-* `member` - (Optional) Members to add to the environment. Each member has `external_id`, `external_id_type` and `role` values.
+* `member` - (Optional) Members to add to the environment.
+
+### Member Parameters Reference
+
+A `member` takes three parameters:
+
+* `external_id` - (Required) The external ID of the member.
+* `external_id_type` - (Required) The external ID type of the member.
+* `role` - (Required) The role of the member in the environment.
+
 
 ## Attributes Reference