From Longman Dictionary of Contemporary Englishit’s a good thingit’s a good thing (also it’s a good job British English) used to say that you are glad something happened, because there would have been problems if it had not happenedIt’s a good thing you’re at home. I’ve lost my keys.and a good thing/job too British EnglishShe’s gone, and a good thing too. →good
Examples from the Corpus
it’s a good thing• It's a good job you didn't scream.• I think it's a good thing.• MalespeakerIt's a good thing for the area.• Still, it's a good thing from the hunt's point of view that new blood is coming along, surely?• It's a good thing I brought my camera.• I decideit's a good thing that I don't see Sean try to capture Ian's incandescentdance.• So it's a good thing to get one's mind off in one's spare time.• Male speaker It's a good thing we check them - we can find any injuredbirds and help them.• It's a good thing we got here in time, he thought.• It's a good thing you remembered to bring napkins.