First of all, modify your viewdetails.php file to accept a more user-friendly name in the absense of an ID.
So, for example, the request viewdetails.php?name=someCompany would return the same as viewdetails.php?id=t3ut249tun429tu (where that is the random ID of the same row containing the name someCompany).
Then, in a .htaccess file:
RewriteRule ^details/([^/]+)/?$ viewdetails.php?name=$1
Explaination of the Regular Expression:
If the request starts with "details/", followed by 1 or more of any character apart from "/", with an optional "/" on the end.