If you are using Paperless Office:  Sage 100 Desktop --> Paperless Office Module --> Journal and Register Viewer --> Company Code --> Module = I/M --> Select Date Range --> Refresh.  You should find an IA-002544 entry that matches that GL Journal Entry, with the full documentation.  Transaction Register Journal Name is subsidiary module register,  and I/M Daily Transaction Register is GL postings. 

Only reason it wouldn't be there would be the user didn't print to pdf?

If you click the bitmap button on the right side of the list box for the Paperless Viewer (or use the keyboard shortcut Alt-U), you can quickly access the Journal and Register Viewer.

If the PDF journal isn't there, you can query the raw data in Excel, or perhaps use the Explore feature (where you'd have to add a column for the journal #... then filter appropriately).