Other Financial Information - Schedule of Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses recognized	$ 0	$ 2,476	$ 0	$ 539	$ 0	$ 3,015
Corporate
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses recognized	0	497		206		703
Water \| Operating Segments
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses recognized	0	1,147		210		1,357
Emerging Technologies \| Operating Segments
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses recognized	$ 0	$ 832		$ 123		$ 955

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Energy Recovery, Inc. 10-Q