You can compare changes that were made between two revisions of the XBRL documents by creating XBRL blacklines.
Each time you generate XBRL documents, a new revision is stored in the document’s XBRL history. Blacklines compare these revision and identify differences.
The XBRL history and blackline features are found on the XBRL tab of the Projects panel. The Projects panel appears only when a project is open.
Go to the Projects panel and then the XBRL tab to find the Generate XBRL button.
Creating an XBRL Blackline
If you want to compare the current XBRL with a previous state and have not generated XBRL documents for it yet, do that now.
On the XBRL tab of the Projects panel, click the History tab.
In the revision history, select the revision you want to compare with another, and on the Actions drop-down menu shown below, select Create Blackline.
In the Create Blackline dialog box, type a name for this blackline, and then, from the History tab, drag the revision you want to compare with the one you selected. Drag the revision from the History list. Click the X button on either revision if you want to use a different one.
Click Create Blackline. A progress bar is displayed.
After the blackline is created, click the icon that shows the revision numbers to view the blackline in the Wdesk XBRL Viewer.
In the Wdesk XBRL Viewer, you can select which section to view and which attributes to display and hide.
A. Document outline indicates which sections have changed.
B. Blue highlights indicate where XBRL changed in the document.
Understanding Blackline Changes
Blackline changes are displayed the same as track changes. However, blacklines changes do not indicate the user who made the changes. Added sections will display as blue with an underline. Deleted sections will be displayed with a red strikethrough.
All sections with changes will have a blue line to the left of the section name.
Deleted tables will show with red strike through and a large blue line to the left of the table.
Deleted rows are indicated with a red font and strikethrough. If columns have been deleted, a message will appear above the affected table: "Columns have been removed from this table.
Deleting an XBRL Blackline
On the Blackline tab, select the revision you want to delete. From the Actions menu, select Delete Blackline.