Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-03970
Entity Registrant Name	HARSCO CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-1483991
Entity Address, Address Line One	350 Poplar Church Road,
Entity Address, City or Town	Camp Hill,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	17011
City Area Code	717
Local Phone Number	763-7064
Title of 12(b) Security	Common stock, par value $1.25 per share
Trading Symbol	HSC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2,202,849,000
Entity Common Stock, Shares Outstanding		78,514,758
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0000045876
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false