I'm not sure about Laravel 5, but for Laravel 4 I use this (app/start/global.php):
App::error(function(Exception $exception, $code)
{
if (App::isDownForMaintenance()) {
return Response::make("Maintenance, brb.", 503);
}
if (Config::get('app.debug')) return;
switch ($code)
{
case 403: /* permission denied */
case 404: /* not found */
return View::make('_layouts.error_404');
case 500: /* internal error */
default:
return View::make('_layouts.error_500');
}
});