CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 145,013	$ 11,844	$ (79,753)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	122,135	121,839	129,083
Amortization	10,650	8,098	12,403
Change in fair value to the unit adjustment liability and loss on dilution and sale of equity method investment	0	0	58,494
Contract estimated forward loss provision for Harsco Rail Segment	1,800	0	45,050
Loss on early extinguishment of debt	1,127	2,265	35,337
Deferred income tax expense (benefit)	(6,522)	57,349	(7,654)
Equity in income of unconsolidated entities, net	(384)	0	(5,686)
Dividends from unconsolidated entities	88	93	16
Other, net	2,666	749	2,633
Changes in assets and liabilities:
Accounts receivable	(16,881)	(32,012)	16,041
Inventories	(14,706)	19,557	(12,313)
Contract assets	(3,312)	0	0
Accounts payable	18,347	12,554	(20,194)
Accrued interest payable	(154)	438	(3,197)
Accrued compensation	(1,127)	11,126	8,865
Advances on contracts and other customer advances	3,057	(16,811)	14,485
Retirement plan liabilities, net	(33,321)	(21,300)	(20,420)
Other assets and liabilities	(33,527)	3,368	(13,314)
Net cash provided by operating activities	192,022	176,892	159,876
Cash flows from investing activities:
Purchases of property, plant and equipment	(132,168)	(98,314)	(69,340)
Proceeds from sales of assets	11,887	13,418	9,305
Net cash used to acquire businesses	(56,389)	0	(26)
Proceeds from sale of equity investment	0	0	165,640
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	15,527	(18,429)	17,238
Other investing activities, net	0	0	70
Net cash provided (used) by investing activities	(161,143)	(103,325)	122,887
Cash flows from financing activities:
Short-term borrowings, net	1,932	5,061	(2,350)
Current maturities and long-term debt:
Additions	128,858	27,985	720,727
Reductions	(116,988)	(108,280)	(979,567)
Cash dividends paid on common stock	0	0	(4,105)
Dividends paid to noncontrolling interests	(5,480)	(2,445)	(1,702)
Noncontrolling Interest - purchase or sale	477	(3,412)	(4,731)
Stock-based compensation - Employee taxes paid	(3,730)	(1,688)	(91)
Common stock acquired for treasury	(30,011)	0	0
Proceeds from cross-currency interest rate swap termination	0	0	16,625
Deferred pension underfunding payment to unconsolidated affiliate	0	0	(20,640)
Deferred financing costs	(596)	(42)	(16,530)
Other financing activities, net	0	(894)	0
Net cash used by financing activities	(25,538)	(83,715)	(292,364)
Effect of exchange rate changes on cash, including restricted cash	(4,404)	4,478	1,724
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	937	(5,670)	(7,877)
Cash and cash equivalents, including restricted cash, at beginning of period	66,209	71,879	79,756
Cash and cash equivalents, including restricted cash, at end of period	67,146	66,209	71,879
Purchase of businesses, net of cash acquired
Working capital	1,295	0	0
Property, plant and equipment	(3,327)	0	0
Goodwill	(22,518)	0	0
Long-term debt acquired	335
Long-term debt acquired		0	0
Other noncurrent assets and liabilities, net	(32,174)	0	(26)
Net cash used to acquire businesses	$ (56,389)	$ 0	$ (26)