What kind of men were Abram's 318 servants?

Les teaches that when Abram heard his brother—actually his nephew Lot—was taken captive, he armed his trained servants born in his own house, 318. This gives a picture of how large Abram's estate really was, because he had that many hired servants who were fit to be men of war. Les explains that Abram had enough hired servants to come up with 318 military aides, men able to handle the sword. Abram pursued the invading kings all the way to Dan in northern Canaan, divided himself against them by night with his servants, smote them, and utterly defeated them. He pursued them to Hobah, on the left hand of Damascus, and brought back all the goods, Lot, the women, and the people safely.