An important part of the role of being a manager is to delegate authority to others. By doing so, you trust that something you might have to be doing yourself gets done by your people so that you can do other things. If "the other things" includes worrying whether the stuff gets done, then you've created twice as much work for yourself by 1) instantiating the work, and 2) fixing the work. If you had just done the work yourself, you might have saved yourself some time. It's always a gamble but a necessary one when you think about it if you want to make things really happen at a large scale.
When the work is performed, the good manager realizes that he/she didn't really do the work and whenever possible, publicly acknowledges the work of others as their work and not the manager's. Indeed he/she instigated the path towards the work, but holding onto the need to retain credit can often be seen as a manager's pathetic attempt to "take credit" from those that could stand to benefit proportionately more from the assignment of credit.
The manager is able to shed the need to own the credit by his/her own intrinsic strength and confidence. How does one stay strong in this manner? As far as I can tell, it's something to do with being an active self-contributor to society separate from their staff. In other words, the hands-on manager doesn't have to be grabbingly hands-on with their staff's work if they are actively hands-on in another supporting, but not conflicting, domain. True strength comes from real strength. The manager needs to be independently capable along some important dimension in order to remain respectable.
However at the other extreme, being completely hands-off with one's staff's work isn't a good idea. Providing an appropriate level of feedback is critical, otherwise a certain desirable depth of work is not achieved (because the manager is usually more experienced and can contribute the secret sauce of "wisdom" which makes everything always better). Any extra attention given by the manager only increases his/her investment and ownership in the work, and thus makes it even harder to cede credit to his/her people when the time to go public with the ideas come.
Thus the manager needs to be involved at the beginning and during a concept's development (on the in), and promote the other's involvement at the very end (on the out). On the other hand if the manager is not involved at all (generally on the out) until the very end of the process to scoop up most of the credit (swooping to the in), then he/she is certainly a poor example of leadership. In my mind, a good leader is first in, then out because he/she is constantly moving forward without needing to wait for the credit and instead distributing it to his/her team.