[racket] parsing methods for character-based invoices?

I've got character-based invoices from old systems that look roughly 
like (but much bigger):

DATE        DESC               CREDIT   DEBIT
01/01/2013  SERVICES         $1234.50
01/01/2013  PAYMENT                     $1000.00

BALANCE                  $234.50


I don't know exactly how they're formatted, so I'm working from 
examples.  My initial plan was to hand-code a dumb parser with regular 
expressions, but I suspect there's a better way.  In particular, it'd be 
nice to have some leeway as to exact positions of data, and hopefully 
some nice error reporting and recovery abilities.

Can anyone point me towards a parsing technique that would lend itself 
to this problem?

Thanks,
Dave