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Fair value of awards other than options granted during the period.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Note 11 - Stock-based Compensation Plan (Details Textual) $ / shares in Units, $ in Thousands									1 Months Ended	3 Months Ended			12 Months Ended	15 Months Ended
	Mar. 06, 2024 USD ($) shares	Jan. 16, 2024 USD ($) shares	May 08, 2023 USD ($) shares	Mar. 08, 2023 USD ($) shares	Mar. 09, 2022 USD ($) shares	Mar. 08, 2022	Oct. 01, 2021 shares	Mar. 10, 2021 shares	Aug. 31, 2020	Mar. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023	Mar. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2023	Mar. 31, 2024 USD ($) shares
Share-Based Payment Arrangement, Amount Capitalized \| $										$ 0		$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) \| $ / shares										$ 6.55		$ 9.32
Number of Operating Segments				2						3
Share-Based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)										10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)														4 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)										138,838
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)										39,790
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value \| $										$ 463		$ 381
Restricted Stock [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										4 years
Restricted Stock [Member] \| Independent Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										1 year
Restricted Stock [Member] \| Independent Directors [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										25.00%
Performance-Based Restricted Stock [Member] \| Members of The Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)							5,000	18,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested Options Forfeited, Number of Shares (in shares)												6,000
Performance-Based Restricted Stock [Member] \| Members of The Senior Management [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										75.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)										6,000				6,000
Performance-Based Restricted Stock [Member] \| Members of The Senior Management [Member] \| Share-Based Payment Arrangement, Vesting on Third Anniversary of Grant Date [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period (in shares)										12,000
Performance-Based Restricted Stock [Member] \| Members of The Senior Management [Member] \| Share-Based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										100.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)										6,000				6,000
Performance-Based Restricted Stock [Member] \| Members of The Senior Management [Member] \| Vesting on January 1, 2025, Based on Performance Metrics [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										0.00%			50.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range							0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range							150.00%
Performance-Based Restricted Stock [Member] \| Chief Executive Officer and Chief Financial Officer [Member]
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range					0.00%	0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range					150.00%	150.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				18,888	20,493
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted, Fair Value \| $				$ 303	$ 200
Performance-Based Restricted Stock [Member] \| Chief Executive Officer and Chief Financial Officer [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										100.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Probable Final Vesting Percentage										0.00%	50.00%
Performance-Based Restricted Stock [Member] \| President of Environmental Technologies [Member]
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range			0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range			150.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			5,081
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted, Fair Value \| $			$ 108
Performance-Based Restricted Stock [Member] \| President of Environmental Technologies [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										100.00%
Performance-Based Restricted Stock [Member] \| President of Process Technologies [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		8,231
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted, Fair Value \| $		$ 100
Performance-Based Restricted Stock [Member] \| President of Process Technologies [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range		0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range		150.00%
Performance-Based Restricted Stock [Member] \| Chief Executive Officer, Chief Financial Officer, and Division Presidents [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	33,539
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Granted, Fair Value \| $	$ 380
Performance-Based Restricted Stock [Member] \| Chief Executive Officer, Chief Financial Officer, and Division Presidents [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										100.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range	0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range	150.00%
The 2023 Stock Incentive Plan [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount \| $										$ 4,813				$ 4,813
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)										2 years 6 months
Restricted Stock Vesting in Three Years [Member] \| Restricted Stock [Member] \| Vesting Based On Performance Metrics [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage									100.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Lower Range									0.00%
Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights Percentage Upper Range									150.00%