Unfortunately, he didn't seem to be interested in doing is "business." Instead, he wanted to explore the yard in its new and unfamiliar moonlit state. (FWIW, the moonlight in our yard last night was just about bright enough to read by).
Over the next couple of hours, I kept going out and trying to encourage him back inside. Finally, about 11:15, I gave up and went to bed.
About 12:15, I heard him barking and went downstairs to find him finally waiting outside the door wanting to come back in. Needless to say, I wasn't very happy with him.