Hmm, pretty sure that is an inefficient RegEx. It is using the greedy '*' along with the lazy modifier '?'. That causes the matching to do some recursive logic to get the result.
I think a better solution would be this
This is a strait-forward, efficient matching that will pull every character following 'License Number:' up to, but not including, the '-' character. Yes, you could just put a colon instead of the full 'License Number:' string, but it will be patently obvious to anyone else reading the code (or even to you if you have to go back to it in a few months).