Plenty of companies are growing by leaps and bounds today, but few can sustain their growth for many years. Finding the exceptions can be the difference between holding a momentum stock that eventually crashes and owning a growth stock that keeps creating value for years. Buffalo Wild Wings (BWLD), America's Car-Mart (CRMT -2.89%), and Starbucks (SBUX -1.02%) are positioned to grow for years on end, which makes them prime picks for long-term growth investors.

Flying higher on the wings of growth
Buffalo Wild Wings' stock price is up over 50% in the last 12 months, causing many investors to believe the opportunity to buy has passed. Indeed, the stock's 25 forward price-to-earnings multiple is high enough to give most investors pause. However, Buffalo Wild Wings' prospects are so good that today's stock price may seem like it was a bargain when investors look back 10 years from now.

Buffalo Wild Wings same-store sales from investor presentation.

The company's first-quarter results served to bolster the company's position relative to other restaurants in the casual-dining space. First-quarter 2014 sales increased 21% compared to the year-ago quarter and same-store sales increased 6.6% at company-owned restaurants and 5% at franchised restaurants. This continues the chain's robust same-store sales growth in the face of a lackluster U.S. economy.

Buffalo Wild Wings' value is dependent on its ability to maintain high growth for many more years. The company's large remaining market opportunity and outstanding unit economics make unencumbered growth a strong possibility. Management believes room exists for 1,700 locations in the U.S. and Canada, with additional opportunities for international franchises. That implies an opportunity for a 68% increase in restaurant count in the U.S and Canada alone. As locations broaden their menus and increase foot traffic, each additional restaurant becomes even more valuable to shareholders. Buffalo Wild Wings is a growth engine that could reward shareholders for decades to come.

A different kind of sub-prime lender
The next growth company flies under the radar of most investors. America's Car-Mart is a used-car retailer that focuses on financing low-priced cars for poor-credit customers. The average car costs $9,721 and payment terms generally do not extend for more than a few years. The short financing period allows America's Car-Mart to collect in a timely manner and the low price makes payments easier on customers.

Source: America's Car-Mart.

Many investors are afraid to invest in what is essentially a subprime loan business. Adding to their concern, no barriers to entry exist and the business tends to be cyclical. However, America's Car-Mart alleviates some of these concerns by focusing on communities with populations of 50,000 or less, where competing financial institutions are less prevalent and personal relationships create an additional incentive for customers to pay in full and on time. As a result, close to 80% of scheduled payments are collected.

This operating strategy has been extremely profitable for the company; it has been profitable in each of the last 10 years and regularly generates a mid-teens return on equity. The company is also growing steadily; its revenue has more than doubled since 2005, growing at an average of 10% per year. This growth trend should continue as management plans to increase its dealership count by 10% per year for the foreseeable future. If the new dealerships can generate the same return on equity as the existing dealerships, America's Car-Mart could be a bargain at 15 times earnings.

Coffee and everything else consumers could want
Starbucks rounds out the list of growth stocks for long-term investors. The company overcame some setbacks in the last decade and is now determined to maintain high growth in the decades to come. After putting a Starbucks on every imaginable corner in the U.S., the company has shifted its domestic strategy to increasing same-store sales. My Starbucks Rewards points provide further incentive for customers to keep coming back to Starbucks for their morning caffeine fixes, and La Boulange bakery and sandwich items draw them in for lunch. The company is also pushing "Starbucks Evenings," featuring beer and wine, to attract customers later in the day. These efforts are propelling Starbucks' mid-single-digit comparable-sales growth in the U.S.

However, Starbucks' real growth story is abroad. While only one-third of Starbucks' locations reside outside of the Americas, nearly two-thirds of new stores are opened in Asia, Europe, and the Middle East. As China, South Korea, and other rising Asian economies court Western brands, Starbucks has the opportunity to serve those enormous populations and continue its growth story.

Foolish takeaway
Growth stocks aren't just for momentum investors. Long-term investors who buy companies with long runways for growth tend to do well over time. If you're looking to make a long-term investment in a growth stock, Buffalo Wild Wings, America's Car-Mart, and Starbucks should be on your short list.