German to English Art/Literary Poetry & Literature word frequency question

I am translating a test of reading comprehension - the subject reads a short story and then answers questions on it. Because it's a test, one of the important factors is that the words used in the English version must be roughly as common (i.e. as familiar to the reader) as the words in the German version. This is more important than translating words with their exact literal equivalent.

In this extract:-
Es war ein grauer Novembertag, als er sich unsicher der Bankfiliale näherte. Seine Finger spielten mit dem kalten Metall in der Tasche seines Parkas.

it is obviously possible to say "His fingers played with the cold metal in the pocket of his parka". But is the word parka as familiar to English readers as Parka is to Germans (I think of the era when German students seemed to wear parkas as their uniform)? I have a hunch that "parka" is going to be moderately unfamiliar to English readers - in which case we are free to think of a term (although I would prefer to avoid "anorak" :-) that would be roughly as familiar to Eng. readers as "Parka" is to Germans ("reefer jacket" might be a possibility). I would welcome any well-founded comments.