Reconciliation of Basic and Diluted Shares (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Income (loss) from continuing operations, net of tax	$ 9,267	$ (10,550)
Weighted-average shares outstanding - basic (in shares)	80,385	80,238
Dilutive effect of stock-based compensation (in shares)	1,878	0
Weighted-average shares outstanding - diluted (in shares)	82,263	80,238
Earnings (loss) from continuing operations per common share, attributable to Harsco Corporation common stockholders:
Basic (in dollars per share)	$ 0.12	$ (0.13)
Diluted (in dollars per share)	$ 0.11	$ (0.13)