What: Contract research organization ICON PLC (ICLR -1.79%) soared mored than 16% today after the company reported second quarter earnings today that appeared to please investors.

So What: ICON delivered mixed results today, as net revenue during the quarter of $389 million was below analyst expectations of $402 million for the quarter. However, the company managed to expand margins during the quarter, which allowed it to produce earnings-per-share of $0.95, which was well ahead of the $0.89 that analysts were expecting and represented a strong 44% growth over last year's results.

Management expects the new margins to be sustainable as well, raising 2015 earnings guidance by 8%, which are now expected to fall in the range of $3.90 to $4.00 per share. In addition, the company's board approved a further $400 million share repurchase program, 

Now What: I think investors were right to cheer this report, as sustainable margins improvements should allow the company to produce strong earnings growth for the year. The new range that management guided for is well above the $3.67 that analysts are currently expecting.

In addition, even after today's pop shares appear to be trading right around 19 times 2015 earnings estimates, so the $400 million addition to the share repurchase program should create value for shareholders, as it represents almost 9% of the company's current $4.5 billion market cap. 

ICON has been a huge long-term winner for investors, and with analysts expecting long-term earnings growth of more than 13%, I see no reason to believe that ICON's stock can't continue to treat investors well.