How much is too much
Depending on how long and how intensely and the conditions in which you exercised you lose a lot of water from your body.
An averaged sized person can lose up to 2 liters[128oz or about 2 quarts] of water for the first hour or then a little less for each aditional hour in hot enviroment. You need to replace what you lose and you probably can safely double that amount. The timing should not matter.