Maybe I am doing this wrong... here is the scenario. I have a form that saves a User. A user can belong to many distribution lists. I have a multi-select box to show which lists a user belongs to. When I save the form I want to destroy all the lists the user had, and then save the ones selected in the multi-select box.

I am not sure how to easily grab all the ids of the related distribution list.

I know I can loop through the model and add the IDs to an array but is there a better way to save these?

User model 

public function distlist() {
  return $this->belongsToMany('Distlist', 'user_distlist', 'user_id', 'distlist_id');
}

On Save
//get current related IDs for removal
$cur_ids = array();
foreach($user->distlist as $list){
  $cur_ids[] = $list->id;
}

//detach IDs
$user->distlist()->detach($cur_ids);

//add new IDs
$user->distlist()->attach(Input::get('dist_list_id'));

This works fine, but it feels like there should be a better way to "detach all" without looping and building that array, or even a better way to get all the related IDs without the loop?