public static function isItem( $fact )
	{
		$prefix = \XBRL_Types::getInstance()->getPrefixForNamespace( $fact->getNamespaceURI() );
		$name = "{$prefix}:{$fact->getLocalName()}";
		$element = \XBRL_Types::getInstance()->getElement( $name);
		if ( ! $element || ! isset( $element['substitutionGroup'] ) ) return false;

		$result = \XBRL_Types::getInstance()->resolveToSubstitutionGroup( $element['substitutionGroup'] , array( "xbrli:item" ) );
		return $result;
	}