This under-the-radar stock has delivered 50% returns annually since going public.The key to building wealth in the stock market is finding high-quality companies and holding on to them for years. One stock that has provided stellar returns for its shareholders since its 2016 initial public offering (IPO) is Kinsale Capital (KNSL 0.12%).Kinsale Capital isn't exactly a household name, but it has all the makings of a quality investment for the long haul. The specialty insurance company has a strong position in ...