Accounts Receivable and Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Accounts Receivable, Net, Current [Abstract]
Trade accounts receivable	$ 295,847	$ 292,765
Less: Allowance for doubtful accounts	(4,634)	(4,731)
Trade accounts receivable, net	291,213	288,034		$ 288,566
Other receivables	54,182	20,224
Provision (benefit) for doubtful accounts related to trade accounts receivable	372	5,346	$ (38)
Inventories
Finished goods	17,223	26,415
Work-in-process	21,787	24,367
Contracts-in-process	0	45,599
Raw materials and purchased parts	72,194	58,943
Stores and supplies	21,907	22,969
Total inventories	133,111	178,293		118,500
Valued at lower of cost or market:
LIFO basis	80,590	80,644
FIFO basis	8,611	52,832
Average cost basis	43,910	44,817
Total inventories	133,111	178,293		118,500
Excess of inventories valued at current costs over LIFO	36,000	33,000
Change in income as a result of LIFO basis inventory valuation over FIFO basis valuation	600	400	1,300
Contract costs accumulated to date		73,740
Estimated Loss Provisions Offset Against WIP		(28,141)
Contracts-in-process	0	45,599
Provision for Loss on Contracts	9,600	3,000
Contract with Customer, Liability	69,000			$ 64,000
Contract estimated forward loss provision for Harsco Rail Segment	1,800	0	45,050
Revenues	1,722,380	1,607,062	1,451,223
SBB [Member]
Valued at lower of cost or market:
Contract with Customer, Liability		97,900
Revenues	$ 24,200	$ 42,500	$ 200
Contract 1 | SBB [Member]
Valued at lower of cost or market:
Percentage Complete	99.00%
Contract 2 | SBB [Member]
Valued at lower of cost or market:
Percentage Complete	26.00%