Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 77,425	$ 85,266	$ 233,081	$ 252,456
Cost of sales	52,615	56,489	154,176	168,400
Gross profit	24,810	28,777	78,905	84,056
Selling and administrative expenses	18,989	21,823	59,374	65,573
Amortization and earnout expenses	2,050	2,166	5,546	6,480
Restructuring expenses	871	729	1,753	968
Acquisition and integration expenses	368		1,067
Executive transition expenses	1,514		1,514
Loss on divestitures, net of selling costs				70
Income from operations	1,018	4,059	9,651	10,965
Other (expense) income, net	(290)	(73)	1,057	95
Interest expense	(772)	(1,316)	(2,739)	(4,319)
(Loss) income before income taxes	(44)	2,670	7,969	6,741
Income tax expense (benefit)	206	739	1,549	(2,569)
Net (loss) income	(250)	1,931	6,420	9,310
Noncontrolling interest	11		11
Net (loss) income attributable to CECO Environmental Corp.	$ (239)	$ 1,931	$ 6,431	$ 9,310
(Loss) earnings per share:
Basic	$ (0.01)	$ 0.06	$ 0.18	$ 0.27
Diluted	$ (0.01)	$ 0.05	$ 0.18	$ 0.26
Weighted average number of common shares outstanding:
Basic	35,358,913	35,070,449	35,263,688	34,944,056
Diluted	35,358,913	35,624,590	35,471,551	35,522,568