Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net sales	$ 364,768us-gaap_SalesRevenueNet	$ 334,122us-gaap_SalesRevenueNet	$ 319,660us-gaap_SalesRevenueNet
Cost of sales	233,626us-gaap_CostOfGoodsAndServicesSold	217,133us-gaap_CostOfGoodsAndServicesSold	197,414us-gaap_CostOfGoodsAndServicesSold
Gross margin	131,142us-gaap_GrossProfit	116,989us-gaap_GrossProfit	122,246us-gaap_GrossProfit
Selling, engineering and administration	85,095	77,882	77,777
Operating earnings	46,047us-gaap_OperatingIncomeLoss	39,107us-gaap_OperatingIncomeLoss	44,469us-gaap_OperatingIncomeLoss
Interest expense, net	1,135us-gaap_InterestIncomeExpenseNet	1,098us-gaap_InterestIncomeExpenseNet	998us-gaap_InterestIncomeExpenseNet
Earnings before income taxes	44,912	38,009	43,471
Provision for income taxes	15,234us-gaap_IncomeTaxExpenseBenefit	13,392us-gaap_IncomeTaxExpenseBenefit	15,439us-gaap_IncomeTaxExpenseBenefit
Net earnings	$ 29,678us-gaap_NetIncomeLoss	$ 24,617us-gaap_NetIncomeLoss	$ 28,032us-gaap_NetIncomeLoss
Basic
from continuing operations (in dollars per share)	$ 2.07	$ 1.71	$ 1.96
Diluted:
from continuing operations (in dollars per share)	$ 2.06	$ 1.70	$ 1.95
Shares used in computation of earnings per share:
Basic	14,307	14,362	14,332
Impact of dilutive securities	71	78	67
Diluted	14,378	14,440	14,399

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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