Nature of Business and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013 Subsidiary	Dec. 31, 2012
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries		2
Cash restricted		$ 700,000
Cash equivalents, original maturities of highly liquid investments		3 months
Accounts receivables payment period from invoice date		30 days
Capitalized deferred financing costs		2,700,000
Amortization of deferred finance cost	100,000	304,000	227,000
Provision for Estimated losses on uncompleted contracts		0	0
Advertisement expense		500,000	200,000
Non forfeitable dividend rights with holders of common stock		One-for-one basis
Foreign Currency Transaction Gain (Loss)		1,000,000	(100,000)
Patents [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life		17 years
Employment contracts [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible assets, Useful Life		3 years
Met-Pro Technologies LLC ("Met-Pro") [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of wholly owned subsidiaries		10
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		10 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
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
Deferred Charges and Other Assets [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Capitalized deferred financing costs		600,000
Discount to Debt [Member]
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Capitalized deferred financing costs		$ 1,900,000