Good security layered, like an onion. You're thinking about hardening the target - this is good.
However, before they can get to the target in the first place, they have to enter the building.
Before they enter your building, they have to enter your land. Set up your perimeter with PIR sensors and they can't even get onto your property without you knowing about it. At Drago towers weve got full coverage around my front boundary, and it chimes in the house or sends text alerts if were not home. Its impossible to enter my land without us being alerted.
A thief can not steal something if they can't get to it unnoticed.
Unless they have a silent, invisible helicopter it is possible to make it so the thieves simply can not steal something. This idea that "if they want it they'll find away" is, sadly, flawed, and too many people use it as a justification for doing nothing.