Heico Corp. (NYSE: HEI) has quietly been one of the best stocks on the market the past decade, outperforming the S&P 500's total return, 659% to 145%. It's performed so well by steadily growing its core aviation manufacturing business and acquiring companies that have been accretive to earnings. The strong earnings streak continued in the second quarter of fiscal 2018 with double-digit top- and bottom-line growth.