Meaning of 'A rising tide lifts all boats'

This idiom, commonly credited to John F Kennedy, describes the idea that when an economy is performing well, all people will benefit from it.

The exact quote attributed to JFK is this:

"A rising tide lifts all the boats and as Arkansas becomes more prosperous so does the United States and as this section declines so does the United States."

While commonly associated with the economy, this idiom can also be used to illustrate any situation that gets better as a whole by improving one component of it.

For example, in the context of business:

"Our plan is to start retraining our junior staff, and since a rising tide lifts all boats, I would expect the performance of the whole team to improve as a result."