Another dose of strong earnings, this time from Ford, Southwest Airlines, and others, helped push the market higher Thursday. It’s one of the busiest weeks on Wall Street for companies posting their quarterly results. Roughly a third of the S&P 500 index will report earnings. For investors, this week has also been a welcome return to business as usual. Wall Street has been focused for weeks on what’s going on in Washington. So far, earnings have come in pretty much as most money managers expected. Companies are reporting bigger profits, but most of the growth has come from cost-cutting, a trend that hasn’t changed very much since the financial crisis.