It's not a type, Jesus said the wicked will be thrown into Gehenna. Gehenna is a real place.
23 And it shall come to pass, that from one new moon to another, and from one sabbath to another, shall all flesh come to worship before me, saith the LORD. {from one new...: Heb. from new moon to his new moon, and from sabbath to his sabbath}
24 And they shall go forth, and look upon the carcases of the men that have transgressed against me: for their worm shall not die, neither shall their fire be quenched; and they shall be an abhorring unto all flesh.
(Isa 66:23-1 KJV)