One way to thanks such a person is:
Thank you for being so scrupulous.
Thank you for your scrupulous reply.
But I am not sure which one is the better choice.
The following sense is to the point:
scru·pu·lous (of a person or process) diligent, thorough, and extremely attentive to details.
"the research has been carried out with scrupulous attention to detail"
synonyms: careful, meticulous, painstaking, thorough, assiduous, sedulous, attentive, conscientious, punctilious, searching, close, minute, rigorous, particular, strict
"scrupulous attention to detail"
What do you think?