When Columbia Sportswear Co. courted investors ahead of its 1998 public offering, CEO Tim Boyle said the company would eventually be known for footwear, not apparel. “So I guess we’re behind,” joked the typically modest Boyle, during a phone interview this week. But this time there’s unmistakable momentum behind Boyle’s footwear fascination. Columbia Sportswear is coming off a blistering two years of growth during which it repeatedly posted record sales and profits, the stock climbed 67 percent and the company surpassed Adidas America to become the second-largest athletic and outdoor employer in Portland. Two years ago, the company, in its characteristically humble manner, quietly announced the biggest overhaul of its business plan in its 80-plus year history. In the wake of the reset, the company’s margins are growing, and it’s sitting on a mountain of cash with almost no debt, positioning Columbia to enter new markets and funding a $33 million headquarters expansion.