$re = '/(?i)\b([QI]{2}|[Q])[\\\\s || -]{0,2}[0-9]{5,}[\\\\s || -]{0,2}\K[A-Z]{3}\b/m';
$str = 'The quote number is Q-123123-PAD with many QI123123 PAD AB01231231PAD
Q-12311-APD
the the the the the';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php