All-American Muslim, Bingo America, and So You Think You Can Dance. Keep in mind that some of these cases go on longer than the shows themselves.
Do you have the legal right? We start with the premise that the basic idea of a documentary about a famous personality (and his annual event) is not protectable and anyone can pursue it -- unless you've contractually agreed not to. Whether you would prevail in an idea-theft lawsuit depends on your employment agreement, whether your treatment arose to the level of a company trade secret, whether the treatment was copyrightable, and how much of the treatment is used in your production. As a general rule, the more detailed the company's treatment, the harder it will be for you to launch a similar project. Unique details -- a novel line of questioning, an out-of-the-box POV, or previously undiscovered research -- tend to enhance trade secrecy and copyright, and make it easier to prove theft. As for the title, if it's so unique that you want to take it, it's probably a trade secret. Check your employment agreement to determine any post-employment limitations, and keep in mind that you'll have to indemnify your production, so it may be worth getting a legal full-monty.