iXBRL Diagnostic Errors - Incorrect Datatype

A possible diagnostic warning which may appear when generating an iXBRL could read Tagged item's value does not correspond to the datatype of the taxonomy element.

This error is indicating that a given tag has been applied to the content of a different format than it is expecting. 

Example: If the End date of period covered by report tag is misapplied to a generic piece of text, then this will trigger the error as the tag is expecting a date.

Tags have the following types, and content tagged under them need to be of the corresponding type.  Other types of tags do exist, but typically do not come up on Support calls.

String - This is alphanumeric text.  You can freely tag lines with this tag, or tag alphanumeric cells.

Date - This information needs to be presented in a date cell

Boolean - This information needs to be presented as a tick box.

Fixed - This is a blank string, typically tagged as an empty alphanumeric cell.

Monetary - This is an item representing a figure.  You need to tag a numeric cell, and ensure you select the correct Numeric option as it relates to the tag. 
Typically this will be Reporting Currency for figures.  See below.

Please refer to external guidance for detail about the taxonomy, though bear in mind you can generally identify which datatype a tag is based on the icon adjacent to it in the tagging menu. 

Note: Not all possible icons are displayed here.

 - This paragraph symbol corresponds primarily to String tags.

However, note that the string symbol is also used for Boolean and Fixed data types.  For Boolean tags, all tag names contain [true/false] at the end which helps identify them.

There is no marker for Fixed tags. These will give length errors if misapplied to a string.

 - This symbol corresponds to Date tags.

 - This symbol corresponds to Monetary tags.