Issue with overcoming errors when using nokogiri's SAX parser

sax_issue.rb

require 'nokogiri'

class Doc < Nokogiri::XML::SAX::Document
  include Enumerable

  def initialize(xml)
    @xml = xml
  end

  def each(&block)
    @on_record = block
    parse(@xml)
  end

  def parse(xml)
    parser = Nokogiri::XML::SAX::Parser.new(self)
    parser.parse(xml)
  end

  def end_element(name)
    @on_record.call(name) if name == "details"
  end

  def error(str)
    puts str
  end
end

xml = <<XML
<?xml version="1.0" encoding="UTF-8"?>
<streeteasy version="1.5">
  <properties>
    <property url="http://example.com/?foo=bar&yin=yang">
      <location>Somewhere</location>
      <details>Information goes here</details>
    </property>
  </properties>
</streeteasy>
XML

puts Doc.new(xml).count # => 0, but should be 1
puts Nokogiri::XML(xml).xpath("//details").count # => 1