Your link to the details page needs to pass the paging variables.
The link you have on the details page is referencing querying variables that dont exist, you need to pass those variables in the link to the details page so the link back to the results page can use them.
See message 4 of this thread for more details:
showthread.php?t=7794
In this thread, we are talking about links to the update page, but the idea is the same. The difference is that I talk about modifying the forms action on the update page, there is no form on the detail page, so you are just modifying the link on the detail page.