It depends on when the distribution was made, not when the check was deposited. In all likelihood, this was a 2017 distribution and would be reported next year.
If this was a 2016 distribution and you're just getting the check now, contact your employer's payroll or tax department to get a 2016 1099-R form, which should be reported on your taxes. Then do this:
In TurboTax, enter your 1099-R just as it is issued. When back at the summary screen, TurboTax will then ask a series of questions so the program can determine if the amount is taxable or not.
