It is a decent domain for an end user, but I doubt anyone is going to pay much of a premium for it.
A few things to consider -
1.) Roofing is a very tough service field to sell domains in. It is just not a field in general where end users really get domain names.
2.) There are multiple tenses - Roofing, Roofer, Roofers, etc.
3.) The reverse order is a more appealing brand. Kansas Roofing is just a more natural term than Roofing Kansas.
4.) Very few roofing companies operate state wide. They generally operate in cities and metro areas.
An end user would probably rather have the city they service in the domain than the state.
For an end user to pay a premium there generally needs to be limited other options. In this case there are many comparable options.
Brad