So I was watching a documentary last night about the discovery of the Dead Sea Scrolls and in the documentary it is said that the scrolls reveal the Jewish people were still polytheistic and that Monotheism actually originated from Egypt before the Jewish Exodus.
I was under the belief that the Israelites were the ones who created (or discovered) Monotheism.
The documentary was most likely referring to Akenhaten, an ancient Egyptian pharaoh who ruled from c. 1353-1336 B.C. and attempted to supplant traditional Egyptian polytheism with a monotheistic religion centered around the sun god Aten. By contrast, the worship of Yahweh is typically dated to a period during the Iron Age Kingdom of Judah, around the 9th century B.C., and the sort of Judaism we're familiar with wasn't really codified until the Babylonian captivity from 586-539 B.C. Given those dates, it's clear that Aten "won the race," so to speak, but, unlike Judaism, Atenism never really caught on. It was abandoned almost immediately after its founder's death, mainly due to pressure from the cult of Amun, and Akenhaten's successor even changed his name from Tutankhaten ("living image of Aten") to Tutankhamun ("living image of Amun") shortly after his accession. By the third or fourth year of Tutankhamun's reign, Aten's temples, including the grand new capital city of Akhetaten, had been completely abandoned. Subsequent pharaohs even went so far as to write Akenhaten, Tutankhamun, and their two successors out of history, insisting that rule passed from one gods-fearing pharaoh to another.
Edit: Accidentally a word.
Not an answer, but what was the documentary?
I can't speak to the birth of monotheism in Egypt, and it appears there is already an answer dealing with that, but I can lend some general information dealing with early Jewish polytheism.
The early Israelites are commonly thought to have practiced monolatrism or henotheism, a belief in many gods while only worshipping one god. This is present in various sections of the Torah which reference Egyptian or Canaanite gods (for example the Egyptian gods in Exodus 12:12 and the Canaanite gods in Numbers 21:29). Another common example is the first commandment:
You shall have no other gods before me.
which some argue implies the existence of multiple gods with the inclusion of the last two words "before me." I believe there is also some debate whether the use of the plural noun "elohim" references one or multiple gods, for example, in the opening verse:
In the beginning, God/the Gods created the heavens and the earth.
but that's something someone with more knowledge than me would have to comment on.
Similar question: what did the Dead Sea Scrolls reveal about Israelite polytheism?
Early Judaism wasn't polytheistic as much as it was monolatrist. A widely accepted theory is that the Israelite religion (monolatrist) branched off from the Canaanite religion (polytheistic), which eventually directly evolved into Judaism (monotheistic) and Samaritanism (monotheistic). Because Judaism is a direct descendent and replacement of the Israelite religion, it is widely considered to be one continuous religion.