To me it sounds like you need to bind your Eloquent model to the $id passed through the URL. You can do that by inserting it into the boot() method inside your App\Providers\RouteServiceProvider. It would look something like this:

public function boot(Router $router)
{

    parent::boot($router);

    $router->bind('mymodel', function($id)
    {
        return MyModel::findOrFail($id);
    });

}

This can also go into your routes file with something like this:

Route::bind('mymodel', bind('mymodel', function($id)
 {
      return MyModel::findOrFail($id);
 });

there are a couple other places as well but the nice thing is it's really your choice.