One of my astute readers, Eric Lund, hit the nail on the head with his comment:
Is ip default-gateway x.x.x.x set on the switch? It should be on the same segment as your management SVI.This lead me to look again at the IDF configurations. Sure enough the ip default-gateway was set to the default gateway of the old network. We had been using the management ports on the switches to access and configure them from the old HP Procurve production network. When I cut over, I forgot to change those default gateway statements. Thankfully it didn't impact production, but it was one of those head scratchers when it came to managing the network.