The biggest problem with having laundry detergent in the pool is the possible sudsing from the soap-like compounds. As long as you can live with that, it's not a serious problem. There are also surfactants in the detergent that will lower the surface tension of the water, but adding borates to a pool will have a similar effect so that's not a serious problem either. Depending on the type of surfactant, it could be incompatible with some kinds of algaecide such as PolyQuat (incompatible just means the two combine to render each ineffective -- it doesn't mean they explode or anything like that).

Though it's not something you want regularly added to your pool, I don't think it's worth doing a drain/refill to get rid of it. It will eventually get removed through dilution. Some of the ingredients will remain dissolved in the water (the long hydrocarbon chains won't break down) while some will combine with dirt, pollen, etc. and get caught in the filter, similar to a clarifier.

Richard