Most Wdesk permissions are managed in the Admin feature. To learn more about that, read the article Managing Members and Groups.
Accessing XBRL Document Settings
Open your document. On the XBRL tab, make sure that XBRL is turned on. In the right-hand XBRL Outline panel, click the XBRL Document Settings button. 
On the Permissions tab, click Edit Permissions. 
Click the Add Permission button. 
Selecting Individuals and Groups
From here you can select whether to add individual users to the document, or choose between predefined groups. After selecting which permission you want to add, click the Add Permission button, then Apply Changes. 