Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (250)	$ 1,931	$ 6,420	$ 9,310
Other comprehensive income (loss), net of tax:
Interest rate swap loss				(506)
Foreign currency translation gain (loss)	1,365	(1,169)	271	(935)
Comprehensive income	1,115	762	6,691	7,869
Noncontrolling interest	11		11
Comprehensive income attributable to CECO Environmental Corp.	$ 1,126	$ 762	$ 6,702	$ 7,869