オーバーフロー

DjangoのHTMLを以下のように書いたのですが､タイトルのようなエラーがでました｡ blockの対応関係を確認しても､間違ってる箇所を確認できなかったので質問させて頂きます｡

intruder_list.html

{% extends "base.html" %}
{% block title %}IntruderList{% endblock title %}

{% block extrahead %}
<style>
    table {
        margin-top: 8px;
    }
</style>
{% endblock extrahead%}

{% block content %}
    <h3 class="page-header">Intruder's list</h3>
    <a href="{% url 'cms:intruder_add' %}" class="btn btn-default">Add</a>
    <table class="table table-striped table-bordered">
        <thead>
            <tr>Time stamp</tr>
        </thead>
        <tbody>
            { % for intruder in intruders %}
            <tr>
                <td>{{ intruder.name }}</td>
                <td>{{ intruder.timeStamp }}</td>
                <td>
                    <a href="{% url 'cms:intruder_mod' intruder_id=intruder.id %}" class="btn btn-default">Modify</a>
                </td>
            </tr>
            {% endfor %}
        </tbody>
    </table>
{% endblock content %}

base.html

{% load staticfiles %}
<!DOCTYPE html>
<html lang="{{ LANGUAGE_CODE|default:"en-us" }}">
<head>
<meta charset="UTF-8">
<title>{% block title %}IntruderList{% endblock %}</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="{% static 'css/bootstrap.min.css' %}" rel="stylesheet">
<link href="{% static 'css/bootstrap-theme.min.css' %}" rel="stylesheet">
<script src="{% static 'js/jquery-1.11.2.min.js' %}"></script>
<script src="{% static 'js/bootstrap.min.js' %}"></script>
{% block extrahead %}{% endblock %}
</head>
<body>
  <div class="container">
    {% block content %}
      {{ content }}
    {% endblock %}
  </div>
</body>
</html>