What alternative options are available if the document size was too thick to staple
A bigger stapler?
That particular wording sounds just like the notifcation of a machine informing the operator the “document is too thick to staple” - yet a wide format printer was referenced in the subject…
In any event, PrintDriver’s subtle solution is about right. How many sheets is the document and at what weight?
Those large/industrial hand staples can get within 160 sheets of 85gsm paper. An pneumatic/mechanized stapler can get through 250+ Sheets with a big enough staple (a rail, at that point).
Or, you can consider other bindery options - booklet making, coiling, padding, etc