Yes, that's too high for most beers including some stouts. You'll need to either neutralize it with acid, precipitate some of it out with lime or dilute it away with low ion water. The latter is clearly the easiest to do (provided you have RO or other low ion water available). But how much to dilute depends on what else is in the water and the type of beer you are trying to brew. Depending on other mineral content some supplementation of calcium, chloride and possibly sulfate will be required.
More and more brewers who don't want to be bothered with the calculations required to determine dilutions, acid additions and mineral supplementations simply use straight RO water. This can be a great simplifier if your water is variable. For example if the yearly average alkalinity is 141 but it varies from 70 to 210 you would treat quite differently depending on the alkalinity at the time. With RO you simply use enough to swamp the max or do not blend using 100% RO at all times and things are then the same for each brew.
Have a look a the Primer in the Stickies to see how to start out using this approach.