You have multiple Suricata processes on the same interface. I count 5 on igb2. There should usually be only 1. Those multiple processes are chewing up your CPU.
Are you by chance trying to run the Service Watchdog package with Suricata? If so, DON"T! It will cause this issue as it does not understand how Suricata works nor how to properly monitor it.
If you don't have Service Watchdog, then something weird is happening on your box (unless you have a lot of VLANs on igb2). If you do have a lot of VLANs on that interface, I would suggest running on the parent only and not each VLAN.
To kill those errant processes (assuming you don't have multiple Suricata-enabled VLANs on igb2), do this.
Stop Suricata on whatever interface igb2 is (LAN, WAN or whatever).
Look for any remaining Suricata processes using this command:
ps -ax | grep suricata
If you see any for interface igb2, then kill them with:
kill -9 <pid>
That should reduce your CPU utilization to almost nothing with no traffic.