Does rioting impair the economy? In this article, the author looks at some of the indirect effects caused by the rioting in Ferguson, Missouri after the jury's decision not to indict the police officer.  He explains that the rioting has hurt the economy (both short-term and long-term) in Ferguson and other communities where rioting is taking place.  

Are there actual numbers that support this conclusion?  Also, can this conclusion be expanded to say that rioting impairs the economy?
There are no numbers to support the problem specific to Ferguson because it happened recently, and not enough time has passed to assess any effect.

The inflammatory rhetoric of the site you linked to probably stems from this paper http://www.nber.org/papers/w10243 that tries to quantify the effects of the race riots in the 1960s. The authors themselves concede the speciousness of their conclusions by acknowledging that the data they used are not detailed enough to identify the precise mechanisms at work. 

A more thorough study that examined the riots in India between the Hindus and Muslims concluded that the motivation for the riots was primarily economically based. Where there was economic growth, riots decreased. Moreover, rioting in one region had no effect on the rioting of neighboring regions. https://openknowledge.worldbank.com/handle/10986/5432