Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			$ 137,563	$ 310,803
Other comprehensive income (loss) before reclassifications			6,294	12,106
Amounts reclassified from accumulated other comprehensive loss			10,227	8,061
Realized (gains) losses reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment (See Note 4, Equity Method Investments)				3,037
Other comprehensive income (loss) from equity method investee				3,764
Total other comprehensive income (loss)	$ (864)	$ 7,321	16,521	26,968
Less: Other Comprehensive loss attributable to noncontrolling interests			(1,534)	418
Other comprehensive income (loss) attributable to Harsco Corporation			14,987	27,386
Balances	186,896	300,949	186,896	300,949
Cumulative Foreign Exchange Translation Adjustments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			(144,534)	(125,561)
Other comprehensive income (loss) before reclassifications			26,386	(9,502)
Amounts reclassified from accumulated other comprehensive loss			0	0
Realized (gains) losses reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment (See Note 4, Equity Method Investments)				3,079
Other comprehensive income (loss) from equity method investee				3,650
Total other comprehensive income (loss)			26,386	(2,773)
Less: Other Comprehensive loss attributable to noncontrolling interests			(1,534)	425
Other comprehensive income (loss) attributable to Harsco Corporation			24,852	(2,348)
Balances	(119,682)	(127,909)	(119,682)	(127,909)
Effective Portion of Deriviatives Designated as Hedging Instruments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			(1,089)	(400)
Other comprehensive income (loss) before reclassifications			(913)	(2,262)
Amounts reclassified from accumulated other comprehensive loss			185	(129)
Realized (gains) losses reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment (See Note 4, Equity Method Investments)				106
Other comprehensive income (loss) from equity method investee				(266)
Total other comprehensive income (loss)			(728)	(2,551)
Less: Other Comprehensive loss attributable to noncontrolling interests			0	(7)
Other comprehensive income (loss) attributable to Harsco Corporation			(728)	(2,558)
Balances	(1,817)	(2,958)	(1,817)	(2,958)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			(461,094)	(389,696)
Other comprehensive income (loss) before reclassifications			(19,185)	23,873
Amounts reclassified from accumulated other comprehensive loss			10,042	8,190
Realized (gains) losses reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment (See Note 4, Equity Method Investments)				(148)
Other comprehensive income (loss) from equity method investee				380
Total other comprehensive income (loss)			(9,143)	32,295
Less: Other Comprehensive loss attributable to noncontrolling interests			0	0
Other comprehensive income (loss) attributable to Harsco Corporation			(9,143)	32,295
Balances	(470,237)	(357,401)	(470,237)	(357,401)
Unrealized Loss on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			(5)	(31)
Other comprehensive income (loss) before reclassifications			6	(3)
Amounts reclassified from accumulated other comprehensive loss			0	0
Realized (gains) losses reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment (See Note 4, Equity Method Investments)				0
Other comprehensive income (loss) from equity method investee				0
Total other comprehensive income (loss)			6	(3)
Less: Other Comprehensive loss attributable to noncontrolling interests			0	0
Other comprehensive income (loss) attributable to Harsco Corporation			6	(3)
Balances	1	(34)	1	(34)
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Balances			(606,722)	(515,688)
Total other comprehensive income (loss)			14,987	27,386
Balances	$ (591,735)	$ (488,302)	$ (591,735)	$ (488,302)