example-input-with-button.html

<div class="input-group">
  <div class="input-group-btn">
    <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">{{colombiaIdType}} <span class="caret"></span></button>
    <ul class="dropdown-menu">
      <li ng-show="colombiaIdType !== 'NIT'"><a href="" ng-click="colombiaIdType = 'NIT'">NIT</a></li>
      <li ng-show="colombiaIdType !== 'CE'"><a href="" ng-click="colombiaIdType = 'CE'">CE</a></li>
      <li ng-show="colombiaIdType !== 'CC'"><a href="" ng-click="colombiaIdType = 'CC'">CC</a></li>
    </ul>
  </div>
  <input type="text" class="form-control" ng-model="destinationOpts.bankAccountHolderId" placeholder="Número de identidad del destinatario" required validate-id-colombia>
</div>