Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 528,798	$ 546,124	$ 575,408	$ 627,407	$ 623,952	$ 623,042	$ 575,408	$ 623,042
OCI before reclassifications							(17,878)	2,142
Amounts reclassified from AOCI, net of tax							12,177	13,104
Total other comprehensive income (loss)	8,198	(6,240)	(7,659)	(6,307)	14,401	7,152	(5,701)	15,246
Less: OCI attributable to noncontrolling interests							(225)	2,056
OCI attributable to Enviri Corporation							(5,926)	17,302
Ending balance	525,879	528,798	546,124	613,765	627,407	623,952	525,879	613,765
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							(4,355)	1,902
Amounts reclassified from AOCI, net of tax							0	0
Total other comprehensive income (loss)							(4,355)	1,902
Less: OCI attributable to noncontrolling interests							(225)	2,056
OCI attributable to Enviri Corporation							(4,580)	3,958
Ending balance	(188,079)			(209,146)			(188,079)	(209,146)
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							304	3,671
Amounts reclassified from AOCI, net of tax							(1,983)	(547)
Total other comprehensive income (loss)							(1,679)	3,124
Less: OCI attributable to noncontrolling interests							0	0
OCI attributable to Enviri Corporation							(1,679)	3,124
Ending balance	(2,149)			3,281			(2,149)	3,281
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							(13,832)	(3,433)
Amounts reclassified from AOCI, net of tax							14,160	13,651
Total other comprehensive income (loss)							328	10,218
Less: OCI attributable to noncontrolling interests							0	0
OCI attributable to Enviri Corporation							328	10,218
Ending balance	(355,412)			(344,481)			(355,412)	(344,481)
Unrealized Gain (Loss) on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance			15			10	15	10
OCI before reclassifications							5	2
Amounts reclassified from AOCI, net of tax							0	0
Total other comprehensive income (loss)							5	2
Less: OCI attributable to noncontrolling interests							0	0
OCI attributable to Enviri Corporation							5	2
Ending balance	20			12			20	12
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(552,548)	(546,532)	(539,694)	(544,606)	(560,842)	(567,636)	(539,694)	(567,636)
Total other comprehensive income (loss)	6,928	(6,016)	(6,838)	(5,728)	16,236	6,794
Ending balance	$ (545,620)	$ (552,548)	$ (546,532)	$ (550,334)	$ (544,606)	$ (560,842)	$ (545,620)	$ (550,334)