Setting Bootstrap buttons to the same width

I have a bootstrap sidebar that contains a couple buttons. Unfortunately, it looks very ugly and I want each button to be the same size. These buttons are contained in a sidebar and will be stack vertically. I want to avoid setting a pixel number for each button.
Here is the jfiddle
http://ift.tt/1JBabmw

HTML

<div id="reading-sidebar" class="col-xs-3 panel-default">
  <div id="reading-sidebar-title" class="panel-heading">Options
    <button type="button" class="btn btn-xs btn-default pull-right" id="reading-sidebar-hide-btn"><i class="glyphicon glyphicon-remove"></i></button>
      </div>
      <div id="reading-sidebar-contents" class="panel-body">
        <ul class="sidebar-button-list">
          <button type="button" id="pre-reading-btn" class="btn btn-default pull-left"><i class="glyphicon glyphicon-minus"></i>&nbsp;Pre Readings</button><br>
          <button type="button" id="passage-btn" class="btn btn-default pull-left"><i class="glyphicon glyphicon-minus"></i>&nbsp;Passage</button><br>
          <button type="button" id="post-reading-btn" class="btn btn-default pull-left"><i class="glyphicon glyphicon-minus"></i>&nbsp;Post Readings</button><br>
          <button type="button" id="media-btn" class="btn btn-default pull-left"><i class="glyphicon glyphicon-minus"></i>&nbsp;Media</button><br>
          <button type="button" id="question-btn" class="btn btn-default pull-left"><i class="glyphicon glyphicon-minus"></i>&nbsp;Questions</button>
        </ul>
      </div>
    </div>