CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 19,577	$ 10,137
Other comprehensive income (loss):
Foreign currency translation adjustments, net of deferred income taxes of $1,627 and $393 for the three months ended March 31, 2018 and 2017, respectively	12,501	16,561
Net gain (loss) on cash flow hedging instruments, net of deferred income taxes of $(839) and $256 for the three months ended March 31, 2018 and 2017, respectively	2,677	(387)
Pension liability adjustments, net of deferred income taxes of $(325) and $(522) for the three months March 31, 2018 and 2017, respectively	(9,001)	1,205
Unrealized gain (loss) on marketable securities, net of deferred income taxes of $4 and $(3) for the three months ended March 31, 2018 and 2017, respectively	(14)	6
Total other comprehensive income	6,163	17,385
Total comprehensive income	25,740	27,522
Less: Comprehensive income attributable to noncontrolling interests	(3,047)	(1,633)
Comprehensive income attributable to Harsco Corporation	$ 22,693	$ 25,889