Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 546,124	$ 575,408	$ 623,952	$ 623,042	$ 575,408	$ 623,042
OCI before reclassifications					(21,573)	12,190
Amounts reclassified from AOCI, net of tax					7,674	9,363
Total other comprehensive income (loss)	(6,240)	(7,659)	14,401	7,152	(13,899)	21,553
Less: OCI attributable to noncontrolling interests					1,045	1,477
OCI attributable to Enviri Corporation					(12,854)	23,030
Ending balance	528,798	546,124	627,407	623,952	528,798	627,407
Cumulative Foreign Exchange Translation Adjustments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(183,499)		(213,104)	(183,499)	(213,104)
OCI before reclassifications					(27,340)	23,035
Amounts reclassified from AOCI, net of tax					0	0
Total other comprehensive income (loss)					(27,340)	23,035
Less: OCI attributable to noncontrolling interests					1,045	1,477
OCI attributable to Enviri Corporation					(26,295)	24,512
Ending balance	(209,794)		(188,592)		(209,794)	(188,592)
Effective Portion of Derivatives Designated as Hedging Instruments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(470)		157	(470)	157
OCI before reclassifications					3,712	1,554
Amounts reclassified from AOCI, net of tax					(1,721)	320
Total other comprehensive income (loss)					1,991	1,874
Less: OCI attributable to noncontrolling interests					0	0
OCI attributable to Enviri Corporation					1,991	1,874
Ending balance	1,521		2,031		1,521	2,031
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		(355,740)		(354,699)	(355,740)	(354,699)
OCI before reclassifications					2,058	(12,405)
Amounts reclassified from AOCI, net of tax					9,395	9,043
Total other comprehensive income (loss)					11,453	(3,362)
Less: OCI attributable to noncontrolling interests					0	0
OCI attributable to Enviri Corporation					11,453	(3,362)
Ending balance	(344,287)		(358,061)		(344,287)	(358,061)
Unrealized Gain (Loss) on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance		15		10	15	10
OCI before reclassifications					(3)	6
Amounts reclassified from AOCI, net of tax					0	0
Total other comprehensive income (loss)					(3)	6
Less: OCI attributable to noncontrolling interests					0	0
OCI attributable to Enviri Corporation					(3)	6
Ending balance	12		16		12	16
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(546,532)	(539,694)	(560,842)	(567,636)	(539,694)	(567,636)
Total other comprehensive income (loss)	(6,016)	(6,838)	16,236	6,794
Ending balance	$ (552,548)	$ (546,532)	$ (544,606)	$ (560,842)	$ (552,548)	$ (544,606)