Slingshot. Source: Polaris.

In the investing world, there are some stocks that you can count on to see strong seasonal effects. Polaris Industries (NYSE:PII) was once a very good example of a seasonal company, with its lines of snowmobiles seeing the most demand in the months leading up to winter. But Polaris has grown to cover a wide range of off-road vehicles, motorcycles, and other products, and as a result, it has done an impressive job of becoming an all-season powerhouse for long-term investors. Despite the fact that shareholders had started to grow nervous in recent months about Polaris' ability to keep growing at its current pace, Tuesday morning's fourth-quarter earnings report put some of those concerns on the back burner -- but raised new worries for the coming year. Let's take a closer look at how Polaris Industries did during the quarter and whether investors should count on even better things from the power-sports leader in 2015.

How Polaris powered higher in 2014 
Investors have to be pleased at Polaris Industries and its overall numbers for the quarter and the full 2014 year. During the fourth quarter, revenue soared 18% to $1.275 billion, with growth rates between 2 and 3 percentage points faster than investors had expected to see. That capped a record-breaking year for the vehicle maker that saw even faster sales-growth rates of 19%. Polaris also achieved bottom-line success, as earnings per share from continuing operations rocketed higher by 27% to $1.98, soundly beating the $1.94 per share that represented analysts' consensus.

A look at Polaris' segments shows just where the company's strengths and weaknesses lie right now. As much as many winter sports enthusiasts think of Polaris for its snowmobiles, that division makes up only about 11% of total revenue, and so its relatively sluggish 2% growth from year-ago levels didn't materially slow the company's overall growth. Despite more favorable weather coming into the winter season in the U.S., Polaris saw huge plunges in overseas demand, with sales in Russia and Scandinavia falling 25% from year-ago levels.

Source: Polaris.

By contrast, the key off-road vehicle unit saw sales gains of 19%, and given that it accounts for more than three-fifths of Polaris' overall business, that growth helped drive its overall revenue higher. Both Polaris' all-terrain vehicles and its side-by-side vehicles showed promising gains, earning greater market share in the industry. Also, sales of parts, garments, and accessories climbed 21% as buyers of off-road vehicles and motorcycles chose to equip themselves with appropriate gear.

The most successful part of Polaris' operations has been the motorcycle division. Sales jumped 50% as the company started retailing two new motorcycles from its Indian product line, the Roadmaster and the Scout. Polaris also saw continued success with its Slingshot roadster, and the company enjoyed higher sales internationally as well as within the U.S. market. On the other end of the spectrum, revenue from Polaris' small-vehicle division dropped by 11% as European economic weakness weighed on the business, but with the unit accounting for less than 3% of the company's overall sales, Polaris hasn't felt much pain from it, and for the full year, the company actually saw top-line growth of 28% in small vehicles.

Time to put the brakes on Polaris Industries' growth?
Looking forward, though, Polaris gave guidance that won't make every shareholder happy. The 60-year-old company said that earnings would likely come in between $7.22 and $7.42 per share in 2015, representing growth of just 9% to 12% from 2014 figures and quite a bit slower than the 18% growth rate that investors had hoped to see. Similarly, revenue projections for 9% to 12% gains in 2015 were at the low end of investors' expectations and clearly represent a marked slowdown from Polaris' recent pace. In response, shares fell about 2.5% in pre-market trade after the announcement.

Source: Polaris.

Yet there's good reason to think that Polaris might be conservative in its guidance. In addition to its new motorcycle lines, Polaris has introduced a number of new products throughout its business, ranging from nine new 2015 model-year AXYS snowmobiles to 400 new accessories stemming from key acquisitions of Pro Armor and Kolpin in the accessory business. A strategic partnership with power-equipment maker Ariens could help Polaris broaden its appeal to customers who have nonrecreational needs for transportation equipment, and with its expanded production capacity in North America and its new manufacturing plant in Poland, Polaris clearly has the ability to ramp up its capacity.

Polaris has already come a long way from being a niche player in a little-followed field to becoming an innovative growth company tapping a much wider range of demand beyond power-sports enthusiasts. If the company can continue to move in that direction, long-term growth is still well within reach for Polaris Industries in 2015 and beyond.