MadCap Flare was an awesome product. It grew out of the old BlueSky "RoboHelp" suite (which was also awesome) and could be used to output to many different formats (online help, web help, print docs, confluence). It's been a while, but I think you could even use FrameMaker to author and still use Flare to transform output to all its supported formats.
It's been a long time since I immersed myself in this world, so apologies if my memory is less than perfect.
It's been a long time since I immersed myself in this world, so apologies if my memory is less than perfect.