Refactor _id attribute getter

src/Jenssegers/Mongodb/Model.php

@@ -49,7 +49,10 @@ abstract class Model extends \Jenssegers\Eloquent\Model {
      */
     public function getIdAttribute($value)
     {
-        if ($value) {
+        if (!$value && array_key_exists('_id', $this->attributes)) {
+            $value = $this->attributes['_id'];
+        }
+
         // Return _id as string
         if ($value instanceof MongoId) {
             return (string) $value;
@@ -58,17 +61,6 @@ abstract class Model extends \Jenssegers\Eloquent\Model {
         return $value;
     }
 
-        if (array_key_exists('_id', $this->attributes))
-        {
-            // Return _id as string
-            if ($this->attributes['_id'] instanceof MongoId) {
-                return (string) $this->attributes['_id'];
-            }
-
-            return $this->attributes['_id'];
-        }
-    }
-
     /**
      * Define an embedded one-to-many relationship.
      *