Determining the level of detail for requirements is an art.
There are many factors that influence the answer. Who is using the requirements? What is their domain knowledge? What are they using the requirements for? What is their skill level? These are all questions that help determine the level of detail required in the requirements,
You can think of requirements as a method of communication. Depending on who you are talking to and what the message is, changes the detail of the communication.
Keep the recipient and the purpose of the requirements in mind and then make them good enough.