The airport has a page dedicated to USPS and FedEx services. Note that the FAQ link is broken.
Robert submitted a note about the mail drops:
Located to the right of baggage claim
There’s one blurry photo on Google; it looks like the mail drop is behind the escalators/stairs on the ground level between baggage claim and the airport check-in counters. Look for the shield on the floor prior to the escalators/stairs.
Last updated 24 December 2018