Acquisition - Additional Information (Detail) (USD $)	2 Months Ended	3 Months Ended						1 Months Ended	2 Months Ended
	Feb. 20, 2014	Mar. 31, 2014		Mar. 31, 2013		Mar. 31, 2014 Acquisition-related Costs [Member]	Mar. 31, 2014 Fair Value Adjustment to Inventory [Member]	Feb. 21, 2014 Industrial Filtration [Member]	Feb. 20, 2014 Andrew Industries Limited [Member]	Mar. 31, 2014 Andrew Industries Limited [Member]
BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents	$ 7,500,000	$ 7,493,000
Business Combination Purchase Price Borrowings	60,000,000
Payments to Acquire Businesses, Gross									86,700,000
LineOfCreditFacilityMaximumBorrowingCapacity	100,000,000
BusinessAcquisitionCostOfAcquiredEntityTransactionCosts										2,400,000
SalesRevenueNet		125,226,000	[1]	99,029,000	[1]			17,700,000
OperatingIncomeLoss		7,626,000	[1]	6,517,000	[1]			800,000
CostOfGoodsSoldDirectMaterials	2,100,000							1,300,000
ProceedsFromSaleOfAvailableForSaleSecuritiesDebt		2,400,000
AvailableForSaleDebtSecuritiesGrossUnrealizedGain		2,200,000
Revenues						$ 2,400,000	$ 1,300,000

[1] Industrial Filtration segment reports results for the period following the date of acquisition of February 20, 2014 through March 31, 2014.