To add on to what the others have said, "to go idle" means to stop. So the sentence is saying that the crack-down on these schools will be slowing down and stopping.

IMHO, to go idle in this sentence means to become ineffective, fruitless, vain BTW, I've never seen 'go idle' expression before, so just guessing from the meaning and the context.

I've found this article in the newspaper and this quote is actually its title, that's probably why it sounds awkward and strange to you, since I forgot to explain the context. It is about the severe punishments on for-profit schools for their fraudulent practices and unfairly treatment of students, more precisely on bringing legal cases against them. But now, under the new government and new rules, the process has stalled. I suppose this is the moment when the crackdown goes idle. I hope this explanation helps. :)

Are you sure you quoted the quote directly and exactly? It sounds really awkward and strange to me. That may be because of missing context, but I suspect that it has simply not been edited properly at source.