Components of Accumulated Other Comprehensive Loss - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 575,408	$ 623,042
OCI before reclassifications	(11,358)	2,536
Amounts reclassified from AOCI, net of tax	3,699	4,616
Total other comprehensive income (loss)	(7,659)	7,152
Less: OCI attributable to noncontrolling interests	821	(358)
OCI attributable to Enviri Corporation	(6,838)	6,794
Ending balance	546,124	623,952
Cumulative Foreign Exchange Translation Adjustments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(183,499)	(213,104)
OCI before reclassifications	(16,535)	12,446
Amounts reclassified from AOCI, net of tax	0	0
Total other comprehensive income (loss)	(16,535)	12,446
Less: OCI attributable to noncontrolling interests	821	(358)
OCI attributable to Enviri Corporation	(15,714)	12,088
Ending balance	(199,213)	(201,016)
Effective Portion of Derivatives Designated as Hedging Instruments
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(470)	157
OCI before reclassifications	2,865	(2,684)
Amounts reclassified from AOCI, net of tax	(1,002)	124
Total other comprehensive income (loss)	1,863	(2,560)
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Enviri Corporation	1,863	(2,560)
Ending balance	1,393	(2,403)
Cumulative Unrecognized Actuarial Losses on Pension Obligations
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(355,740)	(354,699)
OCI before reclassifications	2,310	(7,227)
Amounts reclassified from AOCI, net of tax	4,701	4,492
Total other comprehensive income (loss)	7,011	(2,735)
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Enviri Corporation	7,011	(2,735)
Ending balance	(348,729)	(357,434)
Unrealized Gain (Loss) on Marketable Securities
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	15	10
OCI before reclassifications	2	1
Amounts reclassified from AOCI, net of tax	0	0
Total other comprehensive income (loss)	2	1
Less: OCI attributable to noncontrolling interests	0	0
OCI attributable to Enviri Corporation	2	1
Ending balance	17	11
Accumulated Other Comprehensive Loss
Components of Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(539,694)	(567,636)
Total other comprehensive income (loss)	(6,838)	6,794
Ending balance	$ (546,532)	$ (560,842)