Leases - Supplemental Cash Flow Information Related to Leases (Details) - USD ($)			6 Months Ended
	Jun. 28, 2019	Jan. 01, 2019	Jun. 30, 2020	Jun. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Cash flows from operating activities - Operating leases			$ 12,384,000	$ 6,743,000
Finance Lease, Interest Payment on Liability			663,000	637,000
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	$ 14.4		67,534,000	50,696,000
Finance leases			$ 1,234,000	$ 1,692,000
Harsco Clean Earth Segment
Right-of-use assets obtained in exchange for lease obligations:
Operating leases		$ 34,000,000