How to get Xml Inner node value using c#

How to get Xml Inner node value using c#

<?xml version="1.0"?>

<Document xmlns="urn:hl7-org:v3" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:sdtc="urn:hl7-org:sdtc">

   <docTime value="19981001064138-0400"/> 

</Document>

Name space: xmlns="urn:hl7-org:v3"

Node: DocTime

C# code:

XDocument doc = XDocument.Parse(xmlData);

var docTime = doc.Descendants(XName.Get("{urn:hl7-org:v3}docTime")).FirstOrDefault().FirstAttribute.Value;

result of docTime: 19981001064138-0400