SEC Filing Details Document Details Form 10-K/A Filing Date Mar 27, 2012 Document Date Dec 31, 2011 Form Description Amendment to a previously filed 10-K Filing Group Annual Filings Company Koppers Holdings, Inc. Issuer Koppers Holdings Inc. Filing Formats View HTML Download PDF Download DOC XBRL XBRL Viewer EX-101.INS - XBRL INSTANCE DOCUMENT 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