One of the "secrets" of good academic writing is writing concisely. This doesn't mean writing tersely – it means using exactly as much detail as you think you need.
Here are some examples of things that contribute not writing concisely:
What is a distracting detail? A distracting detail is something that's true but also not essential to making the argument that you're making in that sentence and in that paragraph.
Consider this nonacademic writing example: Someone asks you, "Do you have a car?" If you're planning a trip and they want to know if you'll have to take public transportation of if you can drive, all you need to say is "Yes." If they're asking about carpooling, saying "Yes, I have a 4-door sedan" is a better answer. "Yes, I have a 4-door sedan and can take three people" is even better because it explicitly states the important implications of your having the 4-door sedan. If they're just asking how you'll get there, though, including these extra pieces of information will be superfluous and distracting.
The important takeaway from this is that context matters. What you need to tell your reader in a given sentence will vary, but should always tie into the topic sentence and the purpose of the paragraph.
You can ask yourself this question: What do I need to tell my reader right now? If you see information that doesn't seem important at that point in your writing, either: