CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 512,218	$ 145,013	$ 11,844
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes of $2,507, $(2,167) and $3,471 in 2019, 2018 and 2017, respectively	15,498	(50,743)	36,011
Net gain (loss) on cash flow hedging instruments, net of deferred income taxes of $1,438, $(1,130) and $(759) in 2019, 2018 and 2017, respectively	(5,106)	2,101	1,897
Pension liability adjustments, net of deferred income taxes of $(3,244), $854 and $(4,084) in 2019, 2018 and 2017, respectively	(10,478)	27,185	25,254
Unrealized gain (loss) on marketable securities, net of deferred income taxes of $(11), $16 and $(12) in 2019, 2018 and 2017, respectively	28	(48)	22
Total other comprehensive income (loss)	(58)	(21,505)	63,184
Total comprehensive income	512,160	123,508	75,028
Less: Comprehensive income attributable to noncontrolling interests	(7,327)	(5,454)	(7,068)
Comprehensive income attributable to Harsco Corporation	$ 504,833	$ 118,054	$ 67,960