Accounts Receivable and Inventories (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2016
Accounts receivable
Trade accounts receivable	$ 322,201		$ 322,201		$ 251,013
Less: Allowance for doubtful accounts	(11,539)		(11,539)		(4,586)
Trade accounts receivable, net	310,662		310,662		246,427
Insurance claim receivable	195,000		195,000		30,000
Other receivables	24,343		24,343		23,770
Provision for doubtful accounts related to trade accounts receivable	1,116	$ 12	6,539	$ (196)
Inventories
Finished goods	13,499		13,499		11,892
Work-in-process	12,394		12,394		20,839
Raw materials and purchased parts	99,394		99,394		61,547
Stores and supplies	24,697		24,697		21,907
Inventories	149,984		149,984		116,185
Inventory for Contracts
Loss provision that exceeds accumulated contract costs	6,400		6,400
Net customer advances	47,200		47,200		67,100
Contract estimated forward loss provision for Harsco Rail Segment					$ 1,800	$ 45,100
Revenues	423,155	351,563	1,103,955	1,015,910
SBB [Member]
Inventory for Contracts
Revenues	$ 5,700	$ 5,000	$ 16,400	$ 20,400
Contract 2 [Member] | SBB [Member]
Inventory for Contracts
Percentage complete	37.00%		37.00%
Harsco Environmental Segment
Revenue from External Customer [Line Items]
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	$ 800		$ 6,200