What do I send the Idaho Tax Commission after a request for information?

Did you send in any quarterly estimated payments to Idaho?  You must have entered some on your tax return.  Seems pretty clear.  If you sent them checks you need proof they cashed the checks.  Ask your bank for copies.  Check your bank account if you made any payments either by check or online direct debit.

check your records because you indicated on your return that you made state estimated tax payments.   the state is saying they don't have the records for some or all of the payments.  if you did they want copies of the front and back of the checks with form 51.  if you did not send back the notice and indicate that you didn't make any. expect a bill or a smaller refund than shown in Turbotax.