Josephus - Curiously Informative

In Chapter III, titled Of The Building Of The Temple of Book VIII of Antiquities of the Jews, titled From the Death of David to the Death of Ahab, I have taken note of a portion of Point #1:

Solomon began to build the temple in the fourth year of his reign, on the second month, which the Macedonians call Artemisius, and the Hebrews Jur; five hundred and ninety-two years after the exodus out of Egypt, but one thousand and twenty years from Abraham's coming out of Mesopotamia into Canaan; and after the Deluge one thousand four hundred and forty years; and from Adam, the first man who was created, until Solomon built the temple, there had passed in all three thousand one hundred and two years.

I find it curious that Josephus gives all of these details, including specific numbers of years:

Post-Exodus = 592 years
Post-Abraham's move into Canaan = 1020 years
Post-Deluge = 1440 years
Post-Adam = 3102 years

What I'm curious about is where did Josephus get his information, since there wasn't an Internet, much less any computers when he was writing his history?!  

I suppose that's a question I will have to put to Pastor John Ward at the next class meeting!