Will iPhone 5S Screen Replacement Void Warranty?

Hello,

I recently dropped my iPhone 5S and it shattered with the Apple designed case on it. I took it to a place called iDoctor where they take iPhones, iPods, or iPads and replace a cracked screen etc. Was it okay to take my iPhone 5S to a third party repair shop to get the screen replaced? Will this cause my warrenty to be voided or lower my traid in value if I trade it in one day?

Thanks,

TechnologyGuy