What does “in the midst of the years” mean in Habakkuk 3:2?

Question

The phrase "in the midst of the years" occurs in some more literal translations of Habakkuk 3:2:

Yahweh, I have heard the report of you, and your work, Yahweh, do I fear. In the midst of the years revive it; in the midst of the years make it known; in wrath remember mercy. (~ESV)

Is this a Hebrew idiom? What does it mean? Does it indicate something about the prophet's perception of himself in the flow of human history? Is the NIV rendering appropriate?—

Renew them in our day, in our time make them known; in wrath remember mercy.

Answer 1

Rashi says:

Your deed. In the midst of the years: 'Your original deed, that You would wreak vengeance for us upon our enemies in the midst of the years of trouble in which we are found.'

revive it: 'Awaken it and restore it.'

in the midst of the years: 'And in the midst of these years let it be known.'

I can't imagine there to be a hidden Hebrew idiom that Rashi was not aware of. Possibly because the Hebrew word for midst (קֶ֫רֶב) is only associated with year (שָׁנִים֙) in Habakkuk that the question was formed, but it seems the NIV is fine.