Sandra's business incurred a casualty loss in 2013. Immediately before the casualty, her business truck had an adjusted basis of $30,000 and a fair market value of $35,000. Immediately after the casualty, the truck had a fair market value of $20,000. Because of the truck damage, Sandra's insurance company provided $10,000 as a reimbursement in 2013. What was Sandra's 2013 casualty loss deduction?