Acquisitions and Dispositions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	9 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Jun. 28, 2019
Business Acquisition [Line Items]
Goodwill	$ 727,882	$ 738,369
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Cash and cash equivalents	3,600
Trade accounts receivable, net	62,500
Other receivables	2,100
Other current assets	7,300
Property, plant and equipment	77,200
Right-of-use assets	25,800
Goodwill	330,100
Intangible assets	242,200		$ 261,100
Other assets	1,200
Accounts payable	(23,100)
Acquisition consideration payable	0
Other current liabilities	(19,700)
Net deferred taxes liabilities	(45,400)
Operating lease liabilities	(19,500)
Other liabilities	(8,600)
Total identifiable net assets of Clean Earth	635,700		635,900
Harsco Clean Earth Segment
Business Acquisition [Line Items]
Goodwill	330,101	$ 330,230
Measurement Period Adjustments
Intangible assets	(18,900)
Total identifiable intangible assets of Clean Earth	200
Harsco Clean Earth Segment | Harsco Clean Earth Segment
Business Acquisition [Line Items]
Cash and cash equivalents			42,800
Cash	(39,200)
Trade accounts receivable, net			63,700
Business Combination Provisional Information Initial Accounting Incomplete Adjustment	(1,200)
Other receivables			800
Business Combination Provisional Information Initial Accounting Incomplete Adjustmen	1,300
Other current assets			8,700
Other Current Assets	(1,400)
Property, plant and equipment			75,600
Property, Plant, and Equipment	1,600
Right-of-use assets			14,400
Right of Use Asset	11,400
Goodwill			313,800
Intangible assets			261,100
Other assets			4,000
Other Assets	(2,800)
Accounts payable			(23,000)
Business Combination, Provisional Information Initial Accounting Incomplete, Adjustment, Accounts Payable	(100)
Acquisition consideration payable			(39,200)
Acquisition Consideration Payable	39,200
Other current liabilities			(18,000)
Other Current Liabilities	(1,700)
Net deferred taxes liabilities			(51,200)
Net deferred Taxes Liability	(5,800)
Operating lease liabilities			(11,100)
Operating lease liabilities	8,400
Other liabilities			$ (6,500)
Other Liabilities	2,100
Measurement Period Adjustments
Intangible assets	(18,900)
Goodwill	$ 16,300