How to write a recursive regex that matches nested parentheses?

I am trying to write a regexp which matches nested parentheses, e.g.:

"(((text(text))))(text()()text)(casual(characters(#$%^^&&#^%#@!&**&#^*!@#^**_)))"

A string like this should be matched, cause all the nested parentheses are closed, instead:

"(((text)))(text)(casualChars*#(!&#*(!))"

Should not, or better, should match at least the first "(((text)))(text)" part.

Actually, my regexp is:

 $regex = '/( (  (\() ([^[]*?)  (?R)?  (\))  ){0,}) /x';

But it does not work properly as I am expecting. How to fix that? Where am I wrong? Thanks!