Nature of Business and Summary of Significant Accounting Policies - Consolidated Financial Statements Include Accounts of Subsidiaries (Detail)	Dec. 31, 2017
CECO Group, Inc. [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
CECO Group Global Holdings LLC [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
CECO Filters, Inc. and Subsidiaries ("CFI") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	99.00%
The Kirk And Blum Manufacturing Company [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
CECO Air Quality Solutions, Inc [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
EFFOX, Inc. ( "Effox") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Fisher-Klosterman, Inc. ("FKI") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Flextor, Inc. ("Flextor") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Adwest Technologies, Inc. ('Adwest') [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Aarding Thermal Acoustics B.V. ("Aarding") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Met-Pro Technologies LLC ("Met-Pro") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%
Peerless Mfg. Co. ("PMFG") [Member]
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest [Line Items]
CECO Group Global Holdings LLC	100.00%