It was up to the journalists. According to the interview Glenn Greenwald did on "Pod Save the World", Snowden gave the journalists a giant dump of documents and

It was up to the journalists. According to the interview Glenn Greenwald did on "Pod Save the World", Snowden gave the journalists a giant dump of documents and they had to go through them to determine what was newsworthy. Snowden also insisted that the journalists give the NSA a chance to ask for documents to be redacted/kept secret and explain why. Again, according to the interview, Snowden explicitly did not want a wikileaks-style dump of everything, all at one or drip-drip-drip.