Every once in a while, great companies see setbacks in the stock market. Perhaps the latest quarter wasn't quite up to expectations, or some litigation news negatively affected the stock. In many cases, when a particular stock sells off, it creates opportunity for the patient investor who is watching and waiting.

Recently, a company called Patterson Companies Inc. reported strong first quarter financial results, but it was just shy of Wall Street consensus estimates. Fact is, this is one interesting company, operating in a great industry. Just look up the company's 10-year stock chart, and you can see its outstanding track record of success. It's been a tremendous wealth creator for stockholders.

The company is based in St. Paul, Minnesota, and it is a distributor of dental, veterinary, and rehabilitation supplies. The company's three main operating units are Patterson Dental Supply, Webster Veterinary Supply, and AbilityOne Products Corp. The company provides its customers with everything from toothbrushes to stationary to veterinary pharmaceuticals. It is a leader in its industry with solid growth prospects over the coming years.

Over the past 10 years, virtually every selloff in the company's stock price provided investors with an excellent opportunity to consider a position. With the stock currently 10 points below its most recent high, it looks like history is repeating itself once again.

This example is but one of many in the stock market today. Exceptional companies with track records of growth and strong management teams usually are overvalued relative to the broader market. The reason is simple: investors are willing to pay more for a company that has delivered on its promises. A successful company with a strong following on Wall Street will often remain highly valued, relative to its peers. As such, it makes sense to consider these kind opportunities when they arise, in the context of a balanced portfolio.