title: OverflowError: Python int too large to convert to C long when converting to datetime
body: <p>I'm reading an excel file with Pandas. One column has dates like this: <code>20160210</code></p>
  
  <p>I want to convert to datetime objects, so:</p>
  
  <pre><code>t = pd.to_datetime(dataframe['date'], format='%Y%m%d')
  </code></pre>
  
  <p>The following error arises:</p>
  
  <pre><code>OverflowError: Python int too large to convert to C long
  </code></pre>
  
  <p>Any idea?</p>