Employee Benefit Plans (Details 3) - Pension Plan $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) market shares	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($)
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)	5.70%
Expected long-term rates of return on plan assets	5.10%	5.70%	5.50%
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 185,000	$ 186,400
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	12,900	13,000
Accumulated benefit obligation	12,900	13,000
Fair value of plan assets	$ 0	$ 0
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Number of capital market results simulated in the model for expected return on plan assets | market	1,000
Period for which results of capital markets are simulated	20 years
Expected long-term rates of return on plan assets for next year (as a percent)	6.00%
Expected long-term rates of return on plan assets	6.80%	7.00%	7.00%
Number of shares of Company's common stock included in plan assets | shares	310,000	310,000
Fair values of plan assets	$ 186,835	$ 183,292	$ 180,927
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	183,292	180,927
Employer contributions	1,794	7,301
Fair value of plan assets at end of year	$ 186,835	$ 183,292	$ 180,927
U.S. Plans | Domestic equity securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	3.00%	8.80%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 5,556	$ 2,388
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,388
Fair value of plan assets at end of year	$ 5,556	2,388
U.S. Plans | Domestic equity securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	0.00%
U.S. Plans | Domestic equity securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	8.00%
U.S. Plans | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		13,748
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 13,748
Fair value of plan assets at end of year		$ 13,748
U.S. Plans | International equity securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	17.80%	21.00%
U.S. Plans | International equity securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	14.00%
U.S. Plans | International equity securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	24.00%
U.S. Plans | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 33,158	$ 38,398
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38,398
Fair value of plan assets at end of year	$ 33,158	$ 38,398
U.S. Plans | Harsco common stock
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	3.00%	1.30%
U.S. Plans | Fixed income securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	78.00%	65.40%
U.S. Plans | Fixed income securities | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	73.00%
U.S. Plans | Fixed income securities | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	83.00%
U.S. Plans | U.S. Treasuries and collateralized securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 21,924	$ 15,673
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	15,673
Fair value of plan assets at end of year	21,924	15,673
U.S. Plans | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	123,743	104,166
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	104,166
Fair value of plan assets at end of year	$ 123,743	$ 104,166
U.S. Plans | Other
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	0.30%	3.90%
U.S. Plans | Other | Minimum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	0.00%
U.S. Plans | Other | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	5.00%
U.S. Plans | Cash and cash equivalents
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	0.90%	0.90%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 1,690	$ 1,681
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,681
Fair value of plan assets at end of year	$ 1,690	1,681
U.S. Plans | Cash and cash equivalents | Maximum
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	5.00%
U.S. Plans | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 764	7,238
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	7,238
Fair value of plan assets at end of year	764	7,238
U.S. Plans | Defined Benefit Plan, Equity Securities, Common Stock, Employer, Related Party [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Value of shares of Company's common stock included in plan assets	5,600	2,400
U.S. Plans | Level 1
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	164,147	160,381
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	160,381
Fair value of plan assets at end of year	164,147	160,381
U.S. Plans | Level 1 | Domestic equity securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	5,556	2,388
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	2,388
Fair value of plan assets at end of year	5,556	2,388
U.S. Plans | Level 1 | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		13,748
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	13,748
Fair value of plan assets at end of year		13,748
U.S. Plans | Level 1 | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	33,158	38,398
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	38,398
Fair value of plan assets at end of year	33,158	38,398
U.S. Plans | Level 1 | U.S. Treasuries and collateralized securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 1 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	123,743	104,166
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	104,166
Fair value of plan assets at end of year	123,743	104,166
U.S. Plans | Level 1 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	1,690	1,681
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	1,681
Fair value of plan assets at end of year	1,690	1,681
U.S. Plans | Level 1 | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 2
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	21,924	15,673
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	15,673
Fair value of plan assets at end of year	21,924	15,673
U.S. Plans | Level 2 | Domestic equity securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 2 | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year		0
U.S. Plans | Level 2 | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 2 | U.S. Treasuries and collateralized securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	21,924	15,673
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	15,673
Fair value of plan assets at end of year	21,924	15,673
U.S. Plans | Level 2 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 2 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Level 2 | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	764	7,238
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	7,238
Fair value of plan assets at end of year	764	7,238
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Domestic equity securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Domestic mutual funds—equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year		0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | International equities—mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | U.S. Treasuries and collateralized securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
U.S. Plans | Fair Value Measured at Net Asset Value Per Share [Member] | Partnership [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	764	7,238
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	7,238
Fair value of plan assets at end of year	764	7,238
International Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	606,800	574,500
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	21,800	22,100
Accumulated benefit obligation	20,300	19,900
Fair value of plan assets	$ 8,800	$ 7,900
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)	5.60%
Expected long-term rates of return on plan assets	4.60%	5.30%	5.10%
Fair values of plan assets	$ 637,419	$ 611,667	$ 669,021
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	611,667	669,021
Employer contributions	1,609	14,778
Fair value of plan assets at end of year	$ 637,419	$ 611,667	$ 669,021
International Plans | Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	0.80%	0.90%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	0.00%
International Plans | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 5,298	$ 5,342
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	5,342
Fair value of plan assets at end of year	$ 5,298	$ 5,342
International Plans | Fixed income securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	97.90%	95.00%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	97.50%
International Plans | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 619,014	$ 576,540
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	576,540
Fair value of plan assets at end of year	619,014	576,540
International Plans | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	4,717	4,394
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	4,394
Fair value of plan assets at end of year	$ 4,717	$ 4,394
International Plans | Other
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	0.20%	2.30%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	2.50%
International Plans | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	$ 1,381	$ 14,244
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	14,244
Fair value of plan assets at end of year	$ 1,381	$ 14,244
International Plans | Cash and cash equivalents
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of Plan Assets at December 31	1.10%	1.80%
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Target Long-Term Allocation (less than 5% for Cash and cash equivalents)	0.00%
Fair values of plan assets	$ 7,009	$ 11,147
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	11,147
Fair value of plan assets at end of year	7,009	11,147
International Plans | Level 1
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	7,009	11,147
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	11,147
Fair value of plan assets at end of year	7,009	11,147
International Plans | Level 1 | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
International Plans | Level 1 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
International Plans | Level 1 | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
International Plans | Level 1 | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
International Plans | Level 1 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	7,009	11,147
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	11,147
Fair value of plan assets at end of year	7,009	11,147
International Plans | Level 2
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	630,410	600,520
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	600,520
Fair value of plan assets at end of year	630,410	600,520
International Plans | Level 2 | Mutual funds - equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	5,298	5,342
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	5,342
Fair value of plan assets at end of year	5,298	5,342
International Plans | Level 2 | Mutual funds - bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	619,014	576,540
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	576,540
Fair value of plan assets at end of year	619,014	576,540
International Plans | Level 2 | Insurance contracts
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	4,717	4,394
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	4,394
Fair value of plan assets at end of year	4,717	4,394
International Plans | Level 2 | Other mutual funds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	1,381	14,244
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	14,244
Fair value of plan assets at end of year	1,381	14,244
International Plans | Level 2 | Cash and cash equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Fair values of plan assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	$ 0	$ 0
International, Other Than United Kingdom [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Pension plan assets as a percentage of international plan assets	6.00%
United Kingdom
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Expected long-term rates of return on plan assets for next year (as a percent)	5.60%	4.60%
Pension plan assets as a percentage of international plan assets	94.00%