why z-index does not work outside the table?

Question

The screenshot shows a tooltip with position: absolute and a very large z-index, and it works in the table itself, but as soon as I try to move it out of the table, the table container overlaps the tooltip

UPD: I know z-index works for all positions except position: static. In my case position: absolute;

.new .tooltip-container:before {
    position: absolute;
    width: 100px;
    height: 30px;
    content: "";
    top: -10px;
    background: #333333;
    z-index: 10000000000000000000000000;
}