Get the id of a selected value in Selectbox Laravel 5.1

I want to get the id of the selected value or item from a dropdown selectbox because I want to save it in the database. So , I tried passing the it as a value to get it with an hidden field on the page but it does work. How do I do this? Thanks in advance. Appreciate. This is the form page:

<p>{!! Form::select('companyname', array('' => 'Select a Company') + $listCompanies) !!} </p>

@foreach($istCompaniesId as $company)
            @if(companyname->text === $listCompaniesId->value)
                {!! Form::hidden('company_id', $listCompaniesId->value) !!}
            @endif
        @endforeach

This is the controller:

 $listCompanies = Company::where('user_id', '=', Auth::user()->id)->orderBy('companyname', 'desc')->lists('companyname', 'companyname')->toArray();
      $listCompaniesId = Company::where('user_id', '=', Auth::user()->id)->orderBy('companyname', 'desc')->lists('companyname', 'id')->toArray();
        return view('product.create')
        ->with('listCompanies', $listCompanies)
        ->with('listCompaniesId', $listCompaniesId);

via Chebli Mohamed