Settlement check for mortgage insurance

Hi

This past summer I received a check for over a thousand dollars from a former mortgage lender. Apparently  over a decade ago (prior to a refi with another bank) they delayed informing customers that they no longer had to pay  PMI...there was some kind of class action thing and they sent checks to compensate former account holders for PMI they paid unneccesariily plus interest......there was no info about possible tax implications enclosed.....would this be taxable income on the Federal?