Get height of TextArea when wordwrap is enabled?

The following lines of code return a correct value only when carriages are given in the text area. If style.wordwrap is enabled it won't count the automatic new lines, thus giving a wrong result.

 GUIContent textContent = new GUIContent();
 textContent.text = _target.text;
 float H = style.CalcHeight(textContent, scale.width);

Is there any alternative or more correct/official way to get the right height?