Appropriate oil for Generac Generator

We just purchased a home with a Generac Home Generator that's fueled by propane. The instruction manual states-
"Use a high-quality detergent oil classified “For Service SJ or SH.” Detergent oils keep the engine cleaner and reduce carbon deposits. When changing the engine oil, be sure to use 5W-30 engine oil."
My first issue is with the SJ or SH. My research indicates that these are obsolete and that I am good with going with an SN but I want to be certain before I go dumping a new type of oil into generator. Second question is "Detergent oil". Is this simply referring to oil with additives?
Finally, any recommendations about a high quality, readily available oil to use that meets the above requirements?
Thanks!