public function getFactsWithNils()
	{
		if ( $this->nilsFactsCache )
		{
			return $this->nilsFactsCache;
		}
		else
		{
			$nilsFactsCacheExpression = "xfi:facts-in-instance(/xbrli:xbrl)";
			if ( ! is_null( $this->groupFilterExpression ) )
			{
				$nilsFactsCacheExpression .= "[{$this->groupFilterExpression}]";
			}

			// Because this is the first time the facts have been accessed there are only parameters to be used as variables
			$this->nilsFactsCache = BufferedNodeIterator::fromSourceWithClone( $this->evaluateXPath( $this, $nilsFactsCacheExpression, $this->parameters ), false );
			// $this->nilsFactsCache = $this->evaluateXPath( $this, $nilsFactsCacheExpression, $this->parameters );
			return $this->nilsFactsCache; // ->CloneInstance();
		}
	}