Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	CECO	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2014	$ 181,224	$ 264	$ 168,886	$ 19,051	$ (6,621)	$ (356)	$ 181,224
Beginning Balance, Shares at Dec. 31, 2014		26,405,000				(138,000)
Net loss	(5,734)			(5,602)			(5,602)	$ (132)
Common stock dividends	(7,977)			(7,977)			(7,977)
Exercise of stock options and dividend reinvestment issuances	$ 205		205				205
Exercise of stock options and dividend reinvestment issuances, Shares	30,000	36,000
Excess tax benefit from stock options exercised	$ 44		44				44
Share based compensation earned	2,070		2,070				2,070
Share based compensation earned, Shares		13,000
Stock issued for acquisition	72,145	$ 76	72,069				72,145
Stock issued for acquisitions, Shares		7,602,000
Stock repurchase and retirement, Shares		0
Fair value of noncontrolling interest acquired	6,000							6,000
Adjustment for minimum pension/post retirement liability, net of tax	(292)				(292)		(292)
Translation income (loss)	(2,664)				(2,664)		(2,664)
Ending Balance at Dec. 31, 2015	245,021	$ 340	243,274	5,472	(9,577)	$ (356)	239,153	5,868
Ending Balance, Shares at Dec. 31, 2015		34,056,000				(138,000)
Translation (loss) gain, beginning balance at Dec. 31, 2014	(1,743)
Translation (loss) gain, ending balance at Dec. 31, 2015	(4,407)
Minimum pension/post retirement liability adjustment beginning balance at Dec. 31, 2014	(4,878)
Minimum pension/post retirement liability adjustment, ending balance at Dec. 31, 2015	(5,170)
Accumulated other comprehensive loss, beginning balance at Dec. 31, 2014	(6,621)
Accumulated other comprehensive loss, activity	(2,956)
Accumulated other comprehensive loss, ending balance at Dec. 31, 2015	(9,577)
Net loss	(38,254)			(38,218)			(38,218)	(36)
Common stock dividends	(8,995)			(8,995)			(8,995)
Exercise of stock options and dividend reinvestment issuances	$ 1,515	$ 2	1,513				1,515
Exercise of stock options and dividend reinvestment issuances, Shares	195,000	215,000
Excess tax benefit from stock options exercised	$ 137		137				137
Restricted stock units issued	(9)		(9)				(9)
Restricted stock units issued, Shares		17,000
Share based compensation earned	2,458	$ 1	2,457				2,458
Share based compensation earned, Shares		27,000
Issuance of shares for cashless warrant exercise		$ 1	(1)
Issuance of shares for cashless warrant exercise, Shares		90,000
Stock repurchase and retirement	(1,238)	$ (1)	(1,237)				(1,238)
Stock repurchase and retirement, Shares		(105,000)
Noncontrolling interest acquisitions	(7,088)		(1,256)				(1,256)	$ (5,832)
Adjustment for minimum pension/post retirement liability, net of tax	87				87		87
Interest rate swap	312				312		312
Translation income (loss)	(3,864)				(3,864)		(3,864)
Ending Balance at Dec. 31, 2016	190,082	$ 343	244,878	(41,741)	(13,042)	$ (356)	190,082
Ending Balance, Shares at Dec. 31, 2016		34,300,000				(138,000)
Translation (loss) gain, ending balance at Dec. 31, 2016	(8,271)
Minimum pension/post retirement liability adjustment, ending balance at Dec. 31, 2016	(5,083)
Accumulated other comprehensive loss, activity	(3,465)
Accumulated other comprehensive loss, ending balance at Dec. 31, 2016	(13,042)
Interest rate swap liability adjustment ending balance at Dec. 31, 2016	312
Net loss	(3,029)			(3,029)			(3,029)
Cumulative effect adjustment adopting ASU 2016-09 (See Note 1)	66		177	(111)			66
Common stock dividends	(7,792)			(7,792)			(7,792)
Exercise of stock options and dividend reinvestment issuances	$ 1,295	$ 3	1,292				1,295
Exercise of stock options and dividend reinvestment issuances, Shares	292,000	291,000
Restricted stock units issued	$ (135)	$ 1	(136)				(135)
Restricted stock units issued, Shares		92,000
Share based compensation earned	1,959		1,959				1,959
Share based compensation earned, Shares		25,000
Stock repurchase and retirement, Shares		0
Adjustment for minimum pension/post retirement liability, net of tax	(78)				(78)		(78)
Interest rate swap	180				180		180
Translation income (loss)	4,021				4,021		4,021
Ending Balance at Dec. 31, 2017	186,569	$ 347	$ 248,170	$ (52,673)	$ (8,919)	$ (356)	$ 186,569
Ending Balance, Shares at Dec. 31, 2017		34,708,000				(138,000)
Translation (loss) gain, ending balance at Dec. 31, 2017	(4,250)
Minimum pension/post retirement liability adjustment, ending balance at Dec. 31, 2017	(5,161)
Accumulated other comprehensive loss, activity	4,123
Accumulated other comprehensive loss, ending balance at Dec. 31, 2017	(8,919)
Interest rate swap liability adjustment ending balance at Dec. 31, 2017	$ 492