Can my work be tracked while I'm at the office? Can my boss read my emails and documents?

I work at an office where we all have our own laptops. We're not on a network or a server but I use their wireless internet. Can they still track what websites I visit, read my e-mails or Word documents, etc... and if they can see the websites I visit, can they break into the sites that require passwords like my bank records or personal email account?