Add class to top level menu item if it has multiple child levels

Not sure, but maybe something like this will work? Add to the functions.php.
See explanation here.

//This function is responsible for adding "my-parent-item" class to parent menu item's
function add_menu_parent_class( $items ) {
$parents = array();
foreach ( $items as $item ) {
    //Check if the item is a parent item
    if ( $item->menu_item_parent && $item->menu_item_parent > 0 ) {
        $parents[] = $item->menu_item_parent;
    }
}

foreach ( $items as $item ) {
    if ( in_array( $item->ID, $parents ) ) {
        //Add "menu-parent-item" class to parents
        $item->classes[] = 'my-parent-item';
    }
}

return $items;
}

//add_menu_parent_class to menu
add_filter( 'wp_nav_menu_objects', 'add_menu_parent_class' ); 

So if you can use Jquery you can do it like this:

$('ul li.menu-parent-item:has(ul ul)').addClass('your class');