There is no single ideal body weight, only a healthy weight range. Find out what your ideal weight is for your height with the height/weight chart.
Weight scales can be misleading as an indicator for weight loss success because they measure Total Body Weight and not just fat loss or gain. Scale weight can be affected by eating, drinking, going to the toilet and even hormonal changes. These may affect scale weight but not fat loss.
If a person is exercising regularly, they could be increasing their muscle mass, which will weigh more than the same mass of fat. This in turn will show up on the scales as an increase in total weight even though they may have lost some body fat.
So while weight scales can give you an indication of how you’re progressing, do not become fixated by the scale figure on a daily basis. Always keep sight of your long term health goals.