CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 42,711	$ 19,731	$ 62,288	$ 29,868
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes of $(2,579) and $1,458, and $(952) and $1,851 for the three and six months ended June 30, 2018 and 2017, respectively	(48,706)	9,825	(36,205)	26,386
Net gain (loss) on cash flow hedging instruments, net of deferred income taxes of $(1,046) and $611, and $(1,885) and $867 for the three and six months ended June 30, 2018 and 2017, respectively	2,902	(341)	5,579	(728)
Pension liability adjustments, net of deferred income taxes of $(288) and $(522), and $(613) and $(1,044) for the three and six months ended June 30, 2018 and 2017, respectively	28,627	(10,348)	19,626	(9,143)
Unrealized gain (loss) on marketable securities, net of deferred income taxes of $4 and $-, and $8 and $(3) for the three and six months June 30, 2018 and 2017, respectively	(13)	0	(27)	6
Total other comprehensive loss	(17,190)	(864)	(11,027)	16,521
Total comprehensive income	25,521	18,867	51,261	46,389
Less: Comprehensive (income) loss attributable to noncontrolling interests	296	(1,841)	(2,751)	(3,474)
Comprehensive income attributable to Harsco Corporation	$ 25,817	$ 17,026	$ 48,510	$ 42,915