No surprise here. Democrats always vote early, wherever the option is available.
That was the entire reason for the adoption of early voting: Democrats, dominated by government labor unions, lobbied for it.
A significant organizational advantage of public sector unions (in particular: SEIU, AFSCME, NEA and AFT) is that they distribute ballots to their members and collect them, or else motivate members to get out and vote. For Democrats always, of course.