Nature of Business and Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions		12 Months Ended
	Jul. 12, 2016	Dec. 31, 2018	Dec. 31, 2017 USD ($) Subsidiary Building Land Equipment shares	Dec. 31, 2016 USD ($) Building Land Equipment shares	Dec. 31, 2015 USD ($) shares	Jan. 01, 2017 USD ($)
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Cash equivalents and restricted cash, original maturities of highly liquid investments			3 months
Accounts receivables payment period from invoice date			30 days
Number of building held for sale | Building			3	2
Number of tracts of land held for sale | Land			2	2
Number of equipment held for sale | Equipment			1	1
Property, Plant and Equipment, Useful Life			13 years
Incurred or capitalized deferred financing costs			$ 700,000	$ 0	$ 2,900,000
Percentage of Completion Revenue				7,900,000
Provision for Estimated losses on uncompleted contracts			0	0
Advertisement expense			$ 900,000	$ 900,000	$ 1,000,000
U.S. federal corporate statutory tax rate			35.00%
One-time transition tax period payable on mandatory deemed repatriation of cumulative foreign earnings			8 years
Transition tax imposed for distributions foreign earnings			$ 0
Provisional amounts for GILTI			$ 0
Anti-dilutive options and warrants and unvested restricted stock units outstanding | shares			0.7	1.6	1.5
Foreign Currency Transaction Gain (Loss)			$ 100,000	$ 700,000	$ (1,700,000)
Scenario Forecast [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
U.S. federal corporate statutory tax rate		21.00%
Interest Expense [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Amortization of deferred finance cost			1,000,000	1,100,000	800,000
Discount to Debt [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Capitalized deferred financing costs			$ 2,800,000	$ 3,200,000
Modification of Credit Agreement [Member] | Interest Expense [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Amortization of deferred finance cost					$ 300,000
Tradename [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			10 years
Non-compete Agreements [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			5 years
ASU 2015-11 [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Inventory valued on last-in, first-out method			14.00%	8.00%
ASU 2016-09 [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Discrete tax benefit			$ 400,000
ASU 2016-09 [Member] | Retained Earnings (Loss) [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment to reduce retained earnings						$ 100,000
CECO Filters, Inc. and Subsidiaries ("CFI") [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries | Subsidiary			1
Fisher-Klosterman, Inc. ("FKI") [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries | Subsidiary			3
Met-Pro Technologies LLC ("Met-Pro") [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries | Subsidiary			8
CECO Group, Inc. [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries | Subsidiary			2
Peerless Mfg. Co. ("PMFG") [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries | Subsidiary			5
Ownership percentage by parent	100.00%		60.00%
Percentage of ownership by parent in net income loss	40.00%		80.00%
Maximum [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Installed equipment base with end users			$ 5,000,000,000
Maximum [Member] | Technology [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			10 years
Maximum [Member] | Customer Lists [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			20 years
Maximum [Member] | Building and Improvements [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life			40 years
Maximum [Member] | Machinery and Equipment [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life			15 years
Minimum [Member] | Technology [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			7 years
Minimum [Member] | Customer Lists [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life			5 years
Minimum [Member] | Building and Improvements [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life			5 years
Minimum [Member] | Machinery and Equipment [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life			2 years