From Longman Dictionary of Contemporary Englishbe a stickler for detail/rules/accuracy etcbe a stickler for detail/rules/accuracy etcSTRICTto think that rules etc are very important and that other people should think so too → stickler
Examples from the Corpus
be a stickler for detail/rules/accuracy etc• With his personal guests who were important to him or his state, Kim was a stickler for detail. 