After you process an impairment you can view the cost adjustment activity for the Impairment event on the Open Adjustments tab of the Cost object within the Position Viewer tool.
For each impairment row, you can see an event type of WRITEDOWN or WRITEUP, along with the Impairment Ltd Local (tag 2700) amount and the Impairment Ltd Base (tag 2701) amount. You can also view amortized cost and credit/non-credit loss value (if applicable).