dot the i's and cross all t's: o que isso significa?

I was reading Prior Bad Acts, by Tami Hoag, when I came across a very interesting expression: to dot the i's and cross the t's. Do you have an idea of what that means? To fill you in on what was happening in the book when that expression appeared, two people were discussing whether or not some report on a murder had done carefully and in a lot of details. So one of them asked: "Are you saying Stan Dempsey didn't dot all his i's and cross all his t's on the Hass murders?

So bringing that expression into my routine, it reminds me of something I've been working on very carefully lately, which is my final monograph for college. Everybody knows that depending on the point of the monograph you're at, your levels of care tend to change. So by the end of your work, you tend to take a very close look at all you've written and dot all your i's and cross all your t's. In other words, you make sure your monograph or your report or whatever you've been writing is as accurate as possible. That's all for today guys. Take care!