CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 145,013	$ 11,844	$ (79,753)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes of $(2,167), $3,471 and $(13,670) in 2018, 2017 and 2016, respectively	(50,743)	36,011	(21,560)
Net gain (loss) on cash flow hedging instruments, net of deferred income taxes of $(1,130), $(759) and $(544) in 2018, 2017 and 2016, respectively	2,101	1,897	(682)
Pension liability adjustments, net of deferred income taxes of $854, $(4,084) and $34 in 2018, 2017 and 2016, respectively	27,185	25,254	(71,398)
Unrealized gain (loss) on marketable securities, net of deferred income taxes of $16, $(12) and $(16) in 2018, 2017 and 2016, respectively	(48)	22	26
Total other comprehensive income (loss)	(21,505)	63,184	(93,614)
Total comprehensive income (loss)	123,508	75,028	(173,367)
Less: Comprehensive income attributable to noncontrolling interests	(5,454)	(7,068)	(3,334)
Comprehensive income (loss) attributable to Harsco Corporation	$ 118,054	$ 67,960	$ (176,701)