Possibly Geo-sync orbit?
Many of our satellites are park out there to monitor a certain area. They have no need to cover the entire earth and also at that altitude there would be no junk to hit it, just meteorites and Chinese ASATs.
The orbit for NROL-32 is stated as being high oblique angle, in other words, a high apogee, Molniya orbit. Meaning the mass of the satellite is within that range and that 24 hour coverage over a given area requires at least 3 equi-synchronized satellites.
The Molniya orbit places operations within the Pacific and Indian Oceans area coverage with perigee incursions to Russia and east Asia and the western US Seaboard.
The Eye of Sauron