public function isPrimaryItem( $item )
	{
		if ( ! isset( $item['substitutionGroup'] ) ) return false;
		if ( $item['substitutionGroup'] == XBRL_Constants::$xbrldtHypercubeItem /* 'hypercubeItem' */ ) return false;
		if ( $item['substitutionGroup'] == XBRL_Constants::$xbrldtDimensionItem /* 'dimensionItem' */ ) return false;
		if ( XBRL_Types::getInstance()->resolveToSubstitutionGroup( $item['substitutionGroup'] , array( XBRL_Constants::$xbrldtHypercubeItem  ) ) ) return false;
		if ( XBRL_Types::getInstance()->resolveToSubstitutionGroup( $item['substitutionGroup'] , array( XBRL_Constants::$xbrldtDimensionItem  ) ) ) return false;
		return true;
	}