petedc on "Listing Custom Posts in Custom Taxonomy"

Hi

I have a CT of Staff Department and CP of Staff.

I want to display all the posts listed by e.g:

Parent Category
- Child Category
- Post Name
- Post Name
- Post Name
- Child Category
- Post Name
- Post Name
Parent Category
- Child Category
- Post Name
- Post Name
- Post Name
- Child Category
- Post Name
- Post Name

I have the following code which works fine but only displays the posts under the category it is listed in.

function dc_show_staff(){
    $terms = get_terms( 'staff_department' );

    foreach ( $terms as $term ) {
        $term_name = $term->name;

        $args = array(
                'orderby'   => 'title',
                'order'     => 'ASC',
                'post_per_page' => -1,
                'hide_empty' => 0,
                'tax_query'   => array(
                                array(
                                  'taxonomy' => 'staff_department' ,
                                  'field' => 'slug',
                                  'terms' => $term->slug,
                                  'include_children' => 0
                                )),
                );       

        $term_posts = new WP_Query( $args );

        while( $term_posts->have_posts() ) {
            $term_posts->the_post();

            if ( $term_name ) {
                $output .= '<h3>'.$term_name.'</h3><div class="row">';
                $term_name = '';
            }

            $output .= '<div class="col-sm-2 staff-item">';
            $output .= '<a href="' . get_permalink() . '">' .get_the_post_thumbnail($post->ID , 'thumbnail', 'class=img img-circle img-responsive'). '</a>';
            $output .= '<a href="'.get_permalink().'">'.get_the_title().'</a>';
            $output .= get_post_meta($post->ID, 'job_title', true);
            $output .= '</div>';
        }

        if ( !$term_name ) {
          $output .= '</div>';
        }
    }
    wp_reset_postdata();
    wp_reset_query();

    return $output;
}

How would I modify this to display the Parent Category as a header for each child category? Thanks!