Today the truck was idiling in the driveway while i was dis connecting the boat and it overheated ? I checked all the belts and the pulleys are all turning oil is good water is good.....truck has 75000 miles could it be just a thermostat?

Today the truck was idiling in the driveway while i was dis connecting the boat and it overheated ? I checked all the belts and the pulleys are all turning oil is good water is good.....truck has 75000 miles could it be just a thermostat?
Thank you, I will start with that.How much does the fail safe thermostat run ballpark?
Well disregaurd that last question. I figured it out but im oretty sure the water pump is bad heater hoses are both the same temp,engine is still warming quickly after stat replaced and radiator flushed and not hot air from the heater what so ever.Wrench time.