The interview process for mid-level positions involved paid travel to Arlington, VA headquarters. Interviewers were chosen from different sectors of the company, not just HR. I felt like they were really trying to get to know how I would align with the culture. My initial interview was before the process was formalized, so my knowledge of the current process comes from those who were hired more recently. The Market Based Management system described in the book Good Profit by Charles Koch will familiarize the interviewee with the lingo of the organization, and I highly recommend reading it.