Nature of Business and Summary of Significant Accounting Policies - Schedule of Numerators and Denominators Used to Calculate Basic and Diluted Earnings Per Share (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator (for basic and diluted earnings per share)
Net income attributable to CECO Environmental Corp.	$ 17,417	$ 1,426	$ 8,211
Denominator
Basic weighted-average shares outstanding	34,672,007	35,345,785	35,289,616
Common stock equivalents arising from stock options and restricted stock awards	333	249	231
Diluted weighted-average shares outstanding	35,005,159	35,594,779	35,520,670