SEC Filing Details Document Details Form 10-K Filing Date Feb 24, 2021 Document Date Dec 31, 2020 Form Description Annual report which provides a comprehensive overview of the company for the past year Filing Group Annual Filings Company Koppers Holdings, Inc. Issuer Koppers Holdings Inc. Filing Formats iXBRL View HTML Download PDF Download DOC Download XLS XBRL XBRL Viewer EX-101.SCH - XBRL TAXONOMY EXTENSION SCHEMA EX-101.CAL - XBRL TAXONOMY EXTENSION CALCULATION LINKBASE EX-101.DEF - XBRL TAXONOMY EXTENSION DEFINITION LINKBASE EX-101.LAB - XBRL TAXONOMY EXTENSION LABEL LINKBASE EX-101.PRE - XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE XML - XBRL INSTANCE DOCUMENT