How do I report my gains from a loan payback?

I had a motel Located in Az. about 10 years ago that I sold. the sale included a loan with monthly payments and a balloon at the end.  The loan was paid off in 2016.  There was a final payment of 350K made to me.   How do I report the 350k?  Can't seem to find the right area to report the payment. Capital gains?