SEC Filing Details Document Details Form 8-K Filing Date Sep 14, 2023 Document Date Sep 14, 2023 Form Description Report of unscheduled material events or corporate event Filing Group Current Reports Company Koppers Holdings, Inc. Issuer Koppers Holdings Inc. Filing Formats iXBRL View HTML Download PDF Download DOC Download XLS XBRL XBRL Viewer EX-101.LAB - XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT EX-101.SCH - XBRL TAXONOMY EXTENSION SCHEMA EX-101.PRE - XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT XML - XBRL INSTANCE DOCUMENT