BeautifulSoup parse XML with HTML content

I have an XML file (formally XBRL) in which some of the tags contain escaped HTML. I'd like to parse the document an XML, and then extract the HTML from these tags.
However, it appears that the escaped characters are somehow deleted by BeautifulSoup. So when I try to get mytag.text all the escaped characters (e.g. &lt ;) are not present anymore. For instance:

'<' in raw_text # True
'<' in str(BeautifulSoup(raw_text, 'xml')) # False

I have tried to create a simple example to reproduce the issue, but I haven't been able to do that, in the sense that the simple example I wanted to provide is working without any issue:

raw_text = '<xmltag><t><p>test</p><t><xmltag>'
soup = BeautifulSoup(raw_text, 'xml')
'<' in str(soup) # True 

So you can find the file that I am parsing here: https://drive.google.com/open?id=1lQz1Tfy8u7TBvatP8-QjlnzUi6rNUR79
The code I am using is:

with open('test.xml', 'r') as fp:
    raw_text = fp.read()
soup = BeautifulSoup(raw_text, 'xml')
mytag = soup.find('QuarterlyFinancialInformationTextBlock')
print(mytag.text[:100])
# prints:            div div style="margin-left:0pt;margin-righ
# original file:     <div> <div style=

Try to use another parser for XBRL, i.e. python-xbrl

Check this link- Xbrl parser written in Python

Solutions using simplifieddoc

from simplified_scrapy.simplified_doc import SimplifiedDoc
doc = SimplifiedDoc('<xmltag><t><p>test</p></t></xmltag>')
print (doc.t.html)
print (doc.xmltag.t.html)
print (doc.t.unescape())

result:

<p>test</p>
<p>test</p>
<p>test</p>