Staffer taxonomy-department query

<?php
    $args = array (
        'post_type' => 'staff',
        'tax_query' =>
            array(
                array(
                    'taxonomy' => 'department',
                    'field'    => 'slug',
                    'terms'    => 'your_department',
                    ),
                ),
                );
        $department_query = new WP_Query( $args );

        if ( $department_query->have_posts() ) :
            while ($department_query->have_posts()) : ?>
            <ul class="staffer-archive-list">
            <?php
                $department_query->the_post();
                 ?>
                 <li>
                    <header class="staffer-staff-header">
                        <h3 class="staffer-staff-title">
                            <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
                        </h3>
                    </header>
                    <?php
                        the_post_thumbnail ( 'medium', array ('class' => 'alignleft') );
                        the_excerpt();
                            ?>
                </li>
                <?php
                    endwhile;
                        endif;
                         ?>