In IT there is a misconception that more documentation, procedures, and processes, equals better documentation, procedures, and processes. The fact is that the opposite is true. The first thing that you should implement to avoid tons of documentation, procedures, and processes that may be redundant or contradictory is to, as per best practice; create a solid governance plan that details your procedures and processes.
A good governance plan is a living document that requires constant revision and adjustment to maintain a crisp and agile process. The administrators who do the work should own the processes and maintain them with the help and input of the business stakeholders. I have seen too many businesses where the stakeholders define the policies and procedures thinking only about the business needs and giving little or no thought to the technical side of things, so the documentation and procedures are unrealistic and prone to failure.