Google geocode suggest result is appearing behind the modal - geocoding

Question

I have a problem with google geocode suggest. I have a modal which show a form to complete an address. I have implemented geocode to make easier the address filling, but the suggest is appearing behind the modal, like this:
Some code over here:
JS which implements geocode:
GoogleGeocode = (function () {
var _api = {};
var _googleApiRetrievedOk = false;
var _autocompleteEvent;
var _addressInputId, _zipCodeInputId, _countryInputId, _countryComboboxId;
var _componentToRetrieve = {
street_number: 'short_name',
route: 'long_name',
locality: 'long_name',
administrative_area_level_1: 'short_name',
country: 'long_name',
postal_code: 'short_name'
};
function loadGoogleApis() {
// Importar fuentes
$('head').append($('<link rel="stylesheet" type="text/css" />').attr('href', 'https://fonts.googleapis.com/css?family=Roboto:300,400,500'));
// Importar api Places
$('head').append($('<script type="text/javascript" />').attr('src', 'https://maps.googleapis.com/maps/api/js?v=3.exp&signed_in=true&libraries=places&callback=GoogleGeocode.GoogleGeocodeInit'));
}
function googleGeocodeInit() {
_googleApiRetrievedOk = true;
}
$(document).ready(loadGoogleApis);
return _api;
})();
View which supports modal:
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-footer">
<div class="col-md-6 col-md-offset-1">
<h2>#T("StudentData")</h2>
</div>
<button type="button" class="btn btn-CTA" data-dismiss="modal">X</button>
</div>
<div class="modal-header">
#Html.Action("PrepareStudentDataModel", "Topic")
</div>
</div>
Part of view which calls google geocode:
<div class="form-group row">
<div class="col-md-12">
#Html.TextAreaFor(model => model.Address1, new { #class = "form-control", placeholder = #T("wke.checkout.StudentAddress.geocodeaddress") })
#Html.ValidationMessageFor(model => model.Address1)
<span class="col-md-6 col-xs-6 field-validation-valid" id="StudentAddress_address1MessageValidation" style="visibility: hidden;">
#T("wke.checkout.StudentAddress.messagevalidation")
</span>
</div>
</div>