You have an i7. The cooler is quite capable of maintaining acceptable temps under nominal usage. This is where things get funky. To Intel, acceptable temps is anything under the cpus TDP, which is @100°C. For ppl, acceptable temps is anything under @70°C. For Windows, nominal usage is websurfing, office type production, photoshop etc. For ppl, nominal usage is gaming and rendering. So the values don't line up.
As said, you have an i7. If just using the cores, you'd be fine, lower temps, but the additional threads from hyperthreading is going to seriously increase the workload, which jack's temps through the roof under 100% load values. The cpu while capable of such usage, simply doesn't like such usage without adequate cooling.
Are your temps normal? Absolutely. Are they good? Not in the slightest. The only solution to reduce temps is to lower usage or raise cooling ability.
Basically either turn off hyperthreading while rendering or get a better cooler that has a much higher TDP ability than that Intel stock cooler.
With idle values as high as they are, there's several factors that can contribute, not necessarily just a badly mounted cooler. Airflow is huge, if you have none then your cpu is just sitting in a self made oven and is going to run hot. Ambient temps. If the pc is sitting in high heat areas, it's going to run hot as it's physically impossible to cool a cpu lower than ambient temps by mechanical means. In other words, even at idle, expect the cpu to be 10-15°C hotter than room temp and if it's sitting close to a heat vent, then hotter still. If the room is 80°F, that's 27°C. Add in 15°C for a crappy cooler, that's a cpu at 43°C idle, then add in lousy airflow from only 1 exhaust fan, a gpu adding heat inside and idle temps of 53°C are easily attainable.