About 7 years ago, my husband's brother suddenly died. We received a small inheritance - a bit less than 50k. The money was from an EU country. My husband had to send credit suisse some documentation, I forget what exactly. The taxes were paid in the EU country. When my father in law died a few years later, and a slightly larger amount (still less than 100k) was transfered, no questions asked.

So you might have to document the transfer, maybe not.