Acquisition - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended				9 Months Ended
	Feb. 20, 2014	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Feb. 20, 2014
Business Acquisition [Line Items]
Cash acquired										$ 7,493,000
Borrowings for acquisition of business, amended credit facility										60,000,000
Line of credit facility, maximum borrowing capacity		100,000,000				100,000,000				100,000,000
Net sales		134,227,000		97,995,000		408,246,000		298,075,000
Operating Income (Loss)		5,779,000	[1]	7,386,000	[1]	25,978,000	[1]	23,424,000	[1]
Cost of Goods Sold, Direct Materials	2,100,000
Acquisition-related Costs [Member]
Business Acquisition [Line Items]
Revenues						2,600,000		2,600,000
Amortization of Acquired Intangible Assets [Member]
Business Acquisition [Line Items]
Revenues				200,000
Interest Expense Associated with Borrowings Under the Company's Amended Credit Facility [Member]
Business Acquisition [Line Items]
Revenues				200,000				600,000
Fair Value Adjustment to Inventory [Member]
Business Acquisition [Line Items]
Revenues		200,000				2,100,000		2,500,000
Industrial Filtration [Member]
Business Acquisition [Line Items]
Net sales		30,600,000				82,300,000
Operating Income (Loss)		1,833,000	[1]	0	[1]	4,817,000	[1]	0	[1]
Cost of Goods Sold, Direct Materials		200,000				2,100,000
Andrew Industries Limited [Member]
Business Acquisition [Line Items]
Payments to acquire business	86,900,000
Cash acquired										7,493,000
Post closing adjustment payment		200,000		200,000
Andrew Industries Limited [Member]
Business Acquisition [Line Items]
Acquisition transaction related costs						$ 2,600,000

[1] Industrial Filtration segment reports results for the period following the date of acquisition of February 20, 2014 through September 30, 2014.