Who will be responsible for documenting the business requirements in detail?

Document Controller.

Primarily project manager along with sponsor and client.

i think the managemnet should responsible for the business requirements.first the middle level management after that top level folllow up.

1. The Answer is Accounts Department. Becaus of How you store your accounting documents has a huge impact on your ability to plan ahead. When accounting documents are difficult to retrieve — or go missing — it creates serious problems in the event of a future audit and limits your ability to produce detailed cost analyses and plan budgets.  Effectively managing accounting documents and then preserving them to meet legal and regulatory requirements needs to be a core priority for every finance department.

Document Controller and one copy with Finance manager

Top Management

Industrial Development Department

Auditors

Document Controller

Archive Manager

Board of directors of the company and some times those charged with governance are responsible for documenting the business requirements in detail

Project Manager and Project controller 

As an organized company , DCC department , means documment control department is responsible for each file or document incomming and outgoing, all types to be saved in proper format both as hard copy and soft copy , and but some documents have confidencial in nature can be keep only in Accounts deparment.

Regards

Dilip