Cool. So they just said, "Hey, we would like to offer you the job. Here are the details. Please take your time and let us know when you've made a decision"?
That's right, although they said something like 'Please decide within the week' or something to that effect. I'd have to dig up old, old paperwork to get the exact phrasing, but it wasn't 'Hey dude, it's chill, whenever you make up your mind'