From Halopedia, the Halo wiki
Thorough is an achievement in Halo: Spartan Strike. It is unlocked by completing all Assault Ops for Operations A through E. The achievement is worth 20 Gamerscore. It is represented by a circle with a stack of checked-off papers inside it.
Spartan Strike progress is integrated across the two Microsoft platforms (Windows 8 and Windows Phone 8) as well as across iPad and iPhone, though not between Microsoft and Apple platforms. As such, Assault Ops progress carries across these platforms. Steam does not feature this integration.