Accounts Receivable and Inventories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable, Net, Current [Abstract]
Trade accounts receivable	$ 292,765	$ 248,354
Less: Allowance for doubtful accounts	(4,731)	(11,800)
Trade accounts receivable, net	288,034	236,554
Other receivables	20,224	21,053
Provision for doubtful accounts related to trade accounts receivable	5,346	(38)	$ 13,047
Inventories
Finished goods	26,415	26,464
Work-in-process	24,367	22,815
Contracts-in-process	45,599	54,044
Raw materials and purchased parts	58,943	61,450
Stores and supplies	22,969	22,908
Total inventories	178,293	187,681
Valued at lower of cost or market:
LIFO basis	80,644	79,933
FIFO basis	52,832	64,742
Average cost basis	44,817	43,006
Total inventories	178,293	187,681
Excess of inventories valued at current costs over LIFO	0	33,000
Change in income as a result of LIFO basis inventory valuation over FIFO basis valuation	400	1,300	0
Contract costs accumulated to date	73,740	90,276
Estimated Loss Provisions Offset Against WIP	(28,141)	(36,232)
Contracts-in-process	45,599	54,044
Provision for Loss on Contracts	3,000	6,700
Customer Advances and Deposits	97,900	101,100
Contract estimated forward loss provision for Harsco Rail Segment	$ 0	$ 45,050	$ 0