running electric to my detached garage
You don't need a 60A panel.  In fact it's a bad idea.

Your panel needs to have a shutoff switch*.  It doesn't need a main breaker.  Although... a main breaker happens to work as a shutoff switch.  

Since you're using it only as a shutoff switch and not as a breaker, the breaker size doesn't matter at all.  You can use any panel you please, and in fact, we recommend a large one.  That way you have enough panel spaces for all your needs and on into the future.   

There's nothing worse than running out of spaces in your panel, and now is the time to avoid this - before you buy your panel.  Spend a few extra dollars and get one with a lot of spaces.  Most likely, its main breaker will be larger than 60A.  Like I said, that's fine. 

Your wiring will be protected by the feed breaker in the main panel.  For 10/3 w/ground cable, you must use a 30A breaker.   That may suit your needs.  However if you run 6/3 w/ ground cable, you can use a 60A breaker. 

Remember you must trench direct burial cable to 25", so you have 24" cover over top of the cable, with sand or sifted dirt around it so a rock doesn't dig into the cable. 

Also you will need grounding rods at the garage, even though you are running a ground wire.  You must do both. 



* It needs a shutoff switch because it's in a detached garage.