I have an older door lock that no longer works properly. I cannot find a part or model number, but it says Ideal security on the key side of the assembly. It has a spring-loaded latch which you would turn in addition to the door knob.

It sounds like you have an old Super Guard lock. 

If the lock you are talking about is for a main door and not for a Storm or Screen door, then that is what you are looking for. 

Unfortunately we are not the manufacture of that lock. The manufacturer was called Ideal Security Hardware, and they used to operate in the United States but went out of business over 25 years ago. 

We only have storm and screen door hardware, nothing for main doors.