Income Taxes (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Line Items]
Provisional charge from net deferred tax assets and liabilities revaluation	$ 48,700,000
Income tax expense related to one-time mandatory repatriation of undistributed foreign subsidiary E&P	0
Foreign earnings before tax	89,757,000	$ 20,468,000	$ 18,646,000
Contract estimated forward loss provision for Harsco Rail Segment	0	45,050,000	0
Provisional tax expense on outside basis difference	6,500,000
Differences on international earnings and remittances	700,000	2,000,000
Total international income tax expense	31,700,000	16,300,000
U.S. earnings before tax	5,694,000	(99,939,000)	16,169,000
Provisional tax expense from revaluing the U.S. ending net deferred tax assets	14,900,000
Valuation allowance related to sale of Brand		16,100,000
Operating loss carryforwards	90,193,000	80,178,000
Capital loss carryforwards	11,011,000	18,163,000
Valuation Allowance	174,227,000	146,097,000
Valuation allowance related to foreign tax credit carryfowards	27,300,000
Increase from foreign currency translation	10,100,000
Net increase related to losses in jurisdictions where the asset will not be recognized	6,900,000
Interest and penalties recognized		1,700,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	1,100,000	1,100,000	2,800,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	1,200,000
Capital loss on Equity Investment in Brand
Income Tax Disclosure [Line Items]
Valuation Allowances and Reserves, Balance		16,100,000
Forward loss Provisions in SBB contract
Income Tax Disclosure [Line Items]
Valuation Allowances and Reserves, Balance		13,500,000
Current Year Pension Adjustments recorded through Accumulated Other Comprehensive Income (Loss)
Income Tax Disclosure [Line Items]
Valuation Allowances and Reserves, Balance		19,200,000
Expiring between 2018 and 2021
Income Tax Disclosure [Line Items]
Capital loss carryforwards	11,000,000
International operations
Income Tax Disclosure [Line Items]
Operating loss carryforwards	73,500,000
Operating loss carryforwards not subject to expiration	60,500,000
Operating losses subject to expiration	13,000,000
Unrecognized Tax Benefits, Increase (Decrease) Resulting from Changes in Enacted Legislation			$ (7,800,000)
U.S. state
Income Tax Disclosure [Line Items]
Operating loss carryforwards	16,700,000
U.S. state | Expiring between 2018 and 2022
Income Tax Disclosure [Line Items]
Operating loss carryforwards	3,900,000
U.S. state | Expiring between 2023 and 2027
Income Tax Disclosure [Line Items]
Operating loss carryforwards	2,900,000
U.S. state | Expiring between 2028 and 2032
Income Tax Disclosure [Line Items]
Operating loss carryforwards	4,300,000
U.S. state | Expiring between 2033 and 2038
Income Tax Disclosure [Line Items]
Operating loss carryforwards	5,600,000
United States
Income Tax Disclosure [Line Items]
Differences on international earnings and remittances	$ 6,400,000	$ 7,300,000