What's Herod's Ethnicity?

Deanna asked a great question about Herod descending for the line of the Edomites.

Here's an excerpt from Tyndale Concise Bible Commentary, p. 340: (if you have Libronix, click on the link and it will open to this spot in the book!)

THE EDOMITES AND CHRIST

Even in the New Testament times strife between the Hebrews and Edomites continued in the Jews’ hatred for King Herod who was of Idumean (Edomite) descent. Herod tried to kill the ultimate Representative of Israel, Christ (Matt. 2:1–18). The judgment that would come upon the Edomites because of their cruelty and lack of compassion toward the descendants of Jacob was described in many Old Testament prophecies (cf. Isa. 34:5–15; Jer. 49:7–22; Lam. 4:21–22; Ezek. 25:12–14; Amos 1:11–12).