Set a default Identity Provider when adding new users

When I add a new user manually, the Identity Provider defaults to "Password". We want all our users to use our SSO via SAML. I just imported a larger set of new users via CSV file, and there was no way to set the Identity Provider field. So all imported new users had "Password" as their Identity Provider, and I had to manually go in and change each user.

I would like the ability to set the default Identity Provider to be our SAML SSO configuration for the entire site. I could not see a way to do this on the "Security and single sign-on" page. That way new users that are added, manually or imported, would automatically default to this setting.