The S&P CoreLogic Case-Shiller home price index in the top 20 U.S. markets declined in August for the first time in a year. Cause for concern? Twin Cities area home prices hit an all-time high in June, with a median sales price of $290,000. September’s median sales price of $279,250 was 3.7 percent lower. But seasonal price declines are routine. Monthly price gains from a year ago have steadily been in the 5 to 7 percent range this year.