Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Net sales	$ 176,491us-gaap_SalesRevenueNet	$ 168,288us-gaap_SalesRevenueNet
Cost of sales	98,993us-gaap_CostOfGoodsSold	90,526us-gaap_CostOfGoodsSold
Gross profit	77,498us-gaap_GrossProfit	77,762us-gaap_GrossProfit
Operating expenses:
Research and development and other engineering	10,197	9,700
Selling	22,607us-gaap_SellingAndMarketingExpense	21,819us-gaap_SellingAndMarketingExpense
General and administrative	28,433us-gaap_GeneralAndAdministrativeExpense	26,922us-gaap_GeneralAndAdministrativeExpense
Gain on sale of assets	(16)us-gaap_GainLossOnDispositionOfAssets	(285)us-gaap_GainLossOnDispositionOfAssets
Total operating expenses	61,221us-gaap_OperatingExpenses	58,156us-gaap_OperatingExpenses
Income from operations	16,277us-gaap_OperatingIncomeLoss	19,606us-gaap_OperatingIncomeLoss
Interest (expense) income, net	(35)us-gaap_InterestIncomeExpenseNet	85us-gaap_InterestIncomeExpenseNet
Income before taxes	16,242	19,691
Provision for income taxes	6,191us-gaap_IncomeTaxExpenseBenefit	7,604us-gaap_IncomeTaxExpenseBenefit
Net income	$ 10,051us-gaap_NetIncomeLoss	$ 12,087us-gaap_NetIncomeLoss
Earnings per common share:
Basic (in dollars per share)	$ 0.20us-gaap_EarningsPerShareBasic	$ 0.25us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 0.20us-gaap_EarningsPerShareDiluted	$ 0.25us-gaap_EarningsPerShareDiluted
Number of shares outstanding
Basic (in shares)	49,208	48,899
Diluted (in shares)	49,408	49,065
Cash dividends declared per common share (in dollars per share)	$ 0.140	$ 0.125

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use; (3) to conduct internal product testing; (4) or to provide engineering support to customers in the form of testing services or product uses, specifications or requirements.

No definition available.