This idea that leadership should not get involved in the details might be the worst idea in business.
Because there will always be, by definition, many more detail-level items than big-picture items, most potential causes of failure will be details.
People mistakenly believe leaders shouldn't spend brain cycles on details because they shouldn't *act* at the level of details. OK, you usually don't want executives to literally tighten a bolt themselves, but you do want them to think about that bolt, to care about that bolt, and to ask questions about that bolt.