I'm not sure how extensively used it was as an expression before Idle used it in the sketch - my guess, though, is that it (or similar combinations) were in circulation as some of the myriad of humourous idioms and puns which pepper our social interactions over here. (In that regard, by the way, if you can tolerate a lot of swearing and extreme language, I'd recommend having a dip into Roger's Profanisaurus - it's a book available on Amazon listing English idioms which are (to use a very broad term) rude, but there are lots of free extracts from it online. Brits use these sorts of expressions a fair bit - and the book lists thousands of them).
What the Python sketch did do is to catapult the expression into the country's workplaces and playgrounds the next day and fixed it firmly in the consciousness of a couple of generations here.
Could there be any greater conceit, than for someone to believe that the universe has to be simple enough for them to be able to understand it ?